"Chest Muscles"

In the app, where it says chest muscles, are you meant to pick a random exercise? or are there recommended ones with %'s for you?

All exercises like these follow the same line of thinking.

http://sheiko-program.ru/forum/index.php?topic=477.msg2449#msg2449

Don't pick something at random though. Make sure everything you do has a purpose. That said, exercises listed like that are intended slots for general developmental exercises. That's where you train the muscles instead of training a movement. Think bodybuilding but the purpose isn't for looks, it's to build muscle qualities that will indirectly assist your competition lifts.