Hello friend, as others have stated autoflowers don't like to be stressed as they don't have enough time to recover.
Saying that, alot of people train there autos and the best thing about growing yourself is trying new things and learning from mistakes.
I myself am seeing some success with light lst, defoliation, and tip bending on my autoflowers. Check out my black dog grow compared to my untrained gelato grow.
In my opinion week 3 is getting very late for training an auto and is likely too late as the stems start to really strengthen up at this point.
Good luck and have fun that's what it's all about! Go crazy and experiment my friend. Checkout other people's diaries, find the big auto growers and ask them questions directly :)