I don't completely understand how knights and bishops (according to chess.com) have the same "piece value." If I were to be taking a queen (or rook), should I give up my knight or bishop? So in conclusion, is a knight or bishop more important?
Knights and bishops have very similar value so it's not possible to make a general assessment of which one is better. The specifics of the position will always dictate which piece to prefer. You may want to learn about strategic themes like good/bad bishops (specially in endgames).
Either way, since rooks and queens are almost always stronger than knights and bishops, it won't matter much and the trade will be worth it no matter what. The difficult question is when to trade a bishop for a knight and vice-versa.
It depends on what portion of the game. Towards the beginning, when there are many pieces, the knight is better as it can hop over pieces. Towards the end, when there are less pieces, the bishop is better as it has a larger range than the knight (can move more squares in one direction). This is a general rule, keep in mind that this isn't always the case.