려고 들어가다

go in to do something

"-(으)려고" marks the purpose and 들어가다 is "go in, enter", so together: entered in order to do X. The lines cover entering a physical space — went in to wreck the stage, went in just to mess around, went into the potato field to damage it, went in to rob the place — and entering a line of work or a position: went in to run my own business, went in to learn something, went in saying "I'm here to make 300,000 won".