Unless it's a negated sentence, because if you negate a sentence with Accusative, it takes Genitive instead.
You use the accusative with any verb that takes a direct object. But see Marek's note about the negative.
When to use chłopca and chłopcem? When i was introduced earlier in the course, i understood when to use chłopcem. But the farther i get it seems ive either forgetten how to remember when to use dofferent forms or i just dont understand. I dont know what happened. Earlier, i understood when people talked about "acusative/nominative/genitive/instrumental" etc terms... And now it just confuses me. I think my brain broke because when i read the comments these explanations no longer help me
I forgot to add earlier i was able to test out of level quickly because i understood (or thought i understood) the material and never got an answer wrong. Now i am guessing throigh this section and while im getting the answers right almost 100%, i dont actually understand why they are right or how to actually use it.