You have thrusters in all directions and those are not related to the steering movements. Also make sure you have flight assist ON. You can recognise if that is the case by throttle -set it to 0 and ship should stop within some seconds. That means computer automatically applies reverse throttle so stop you (in space you'd normally continue with the achieved speed even with engine turned off. Acceleration will be 0, but speed would be constant since you have no resistance). If you turn flight assist off you'll start screaming at this stage
no worries,later you might join the FAOFF guys and never use it
I can also advise to leave training and start thr game in Solo! You don't risk anything and can delete the save anytime, if you get lost or do smth terribly wrong. If you crash the rebuy of stock ship is 0,- so no worries. Training missions are nice, but should not cause frustration.. just skip those prescribed scenarios and take a deep dive. We're here and will help anytime.
o7 Commander