Advancing in Subnautica - Easier Than You Think!
Some tips and tricks you can use when you feel that you're stuck in Subnautica.
Some Helpful Blueprints to Have
While you don't need ALL of these blueprints in order to use the rest of this guide, they are helpful in solving your problems (assuming you already have The Scanner):
The Repair Tool - the repair tool is relatively easy to acquire, and I assume you will have found it before you continue this guide. If you have not found it, find the Crashfish (the ones that swim towards you and explode), and once the crashfish has blown up, go back to the plant it was living in. Pick up the sulfer, and you will unlock the blueprint for this tool.
The Radio - fix this in your lifepod with the Repair Tool, and come back to it periodically to listen to distress signals from other lifepods. Going to these lifepods will reward you with blueprints, fragments, and other goodies.
Scanner Room - this room can be found relatively easily, though it takes some exploring to find the fragments. You shouldn't have to go to some of the extreme biomes to locate the fragments, they will be in wrecks around the grassy pleateu and in wrecks surrounding the shallows and the kelp forests.
Beacon - this blueprint is incredibly important, and makes it easier to relocate places of interest and wrecks that you cannot fully salvage, expecially for players who do not have photographic memory.
Cutting Tool - this is very easy, as there are fragments all over the shallows, kelp forests, and grassy pleateu. This tool is necessary to enter certain areas of wrecks, and to explore the Aurora further.
Using the Scanner Room
This room requires a lot of power, but 3 solar panels (not including the ones for your own habitiat) should be plenty to operate this room at all times of the day. Attach it to your base, or give it its own hatch, and enter the room (note: make sure that the room connects correctly, as it only has 2 sides to enter it). On one wall, you should find a panel that has a list of objects that you will recognize; limestone chunks, quartz, metal scrap, even wrecks! Click on one of these items, and the Scanner Room will begin searching for the object you have selected.
I highly recommend getting the Scanner Room HUD upgrade, which can be crafted at the fabricator located only inside the Scanner Room. This will automatically show the locations of objects that the Scanner Room has found, and will always display on your HUD while you are in the Scanner Room's range. This is too useful to pass up.
The Scanner Bots are nice, but they just provide an extra way to explore without going out yourself. These bots just save you time and let you explore without the limitation of your oxygen. If they get themselves around Stalkers, they become bait and are essentially useless.
Note: when you scan for Fragments using the Scanner Room, it will only search for Fragments of blueprints you do not have or are incomplete. It will not show you the location for any Fragments of blueprints you have already obtained. This does help keep your HUD clear of clutter, but sometimes you want to find some Titanium without the chance of Copper taking up inventory space.
Using the Beacons
In the Shallows, there are a number of giant coral tubes that contain lots of resources. You will want to mark these, as you will want to come back and collect all of its resources, even if you have a Waterproof Locker. You'll also want to take a floating air tube, and some air tubes to let you stay underwater longer. You can skip taking those items if there is a Brain Coral nearby, as you can gather oxygen from its bubbles.
The Scanner Room's range is limited, so you will need these beacons to mark the locations of larger wrecks further away from your base of operations.
If you make some secondary bases (which I recommend, as they can provide you with oxygen and even places to store cured food, or indoor growing planters once you eventually find them). Put these bases and Beacons along routes you happen to frequent or travel to often.
When you find a wreck that has a sealed door that requires the Cutting Tool, and you have not acquired the Cutting Tool yet, place a Beacon there, and add a "C" at the end, to remind you to return to this wreck with the Cutting Tool. Name the Beacon like this:
Wreck 3, C
These wrecks are particularly important, but more on that in the Cutting Tool segment.
The Cutting Tool
There isn't much to say about the Cutting Tool, other than you will need it for a couple of times in wrecks, and aboard the Aurora. However, don't neglect this tool, as it will be necessary to find important blueprints and other treasures!
I had to use the Cutting Tool to enter a wreck to find the Modification Station, so build it as soon as you have the resources.
The Cutting Tool requires a lot of power, so bring a spare battery for it (unless you're aboard the Aurora, where you'll find plenty of batteries on board).
While you will likely acquire this blueprint early on, you will not be able to construct the Cutting Tool until you locate the Jellyshroom biome (which you will enevitably find during the story), or when you happen to find the Mountain Island and explore its cave system.
This tool is not something that you will need often, so keep it in your storage at your base until you need it (going aboard the Aurora, for example).
You should by now have already obtained the blueprint for the Seaglide and made one, and you might have bothered building the Mobile Vehicle Bay and constructed the Seamoth. Let me say a few things about the vehicles:
The Seaglide: you should always have this in your inventory, and on your hotbar (the "2" key is the quickest to press from WASD, so assign it to "2" for a quick getaway from predators!). Keeping a spare battery for it is not a bad idea, though you will not need to once you obtain the Charge Fins, which will power your Seaglide as you swim.
The Seamoth: for me, this is my primary mode of transportation. It is the fastest of the vehicles constructed at the Mobile Vehicle Bay, and the easiest to build. You should be using this vehicle a lot while you explore, as it will provide you with oxygen and protection against predatory sea life.
The Cyclops: this is an excellent mobile base, as you can construct a Fabricator, Battery/Power Cell Chargers, Wall Lockers, and other useful items that you would have in your base. It should not become your new home, as its weakness is that it can easily be attacked by predators, while your stationary base does not attract predators.
The Prawn: unless you have the Drill Arm for the Prawn, there is little point in building one. It's cool, but its uses are limited without its arm upgrades. You will have seen some large deposits of minerals scattered about that you cannot mine by this point, and only the Prawn's Drill Arm can mine them.
One of your first impulses will be to gather up all of the Scrap Metal to be processed into Titanium, but it is the wrong thing to do. Allow me to explain...
In order to acquire Enameled Glass, you need 1 unit of Glass, and 1 Stalker Tooth. As you cannot slay a Stalker (I have tried and failed MANY times) you must collect Stalker Teeth when they feed on metal objects. Occoasionally, they will lose a tooth, much like sharks in our world, and it will drift to the sea floor, where you can then pick it up for your own uses.
Luckily, the Scanner Room can detect Stalker Teeth, and if you have the upgrade to display their locations on your HUD, you can quickly enter Stalker territory, get the teeth, and get out with minimal injury to yourself.
Aerogel is an important ingredient for a number of blueprints and vehicle upgrades. There are two ingreidents to make it: 1 Ruby, and 1 Gel Sack.
Finding Rubies: as you continue to explore around the islands, you will find Rubies deep underwater. They're bright red, so they're difficult to miss, unless you're moving too quickly in the Seamoth.
Finding Gel Sacks: this particular naturally forming ingredient can be found in and around caves in deeper waters. They have a purple glow, but if you're moving too quickly, you will miss these.
Once you are able to find these two items, it will become easier for you to locate more and craft Aerogel for your vehicles and upgrades.
This ingredient is made by combining Hydrochloric Acid and Gold, and is used for a number of upgrades and at the Modification Station.
How does one get Hydrochloric Acid? You need 3 Deep Shrooms and 1 Salt Deposit.
As you explore the other lifepods, you will find one that will be in particularly deep water. Around this lifepod, you will find Deep Shrooms. Collect as many of them as you can (preferably a number divisable by 3), and return to your base. Salt Deposits are easy to find, so you won't have to look far to find them. Then you can craft Hydrochloric Acid, and in turn Polyanline.