This short guide explains how helpers work.
Short Explanatory Guide to Helpers
You have to drag the helper to the “Equiment” slot for it to attack.
While attacking it looses energy, mine currently has a max of 10 minutes of energy.
At anypoint you can more the helper back to the “Charge” slot to regain the energy.
The “upgrade” slot spends time to uograde the equipment and makes the base damage go up. i did notice, though not sure if intended, that while in the upgrade slot the helper energy charges aswell.