Foundation problems?

hi :) ok so im gonna use foundation for a special event i already bought the revlon colorstay foundation oily skin in 300. but i wanna know if before you put the foundation on your skin do you need to moisturizer because it can break you out or you just can put the foundation on your clean skin??? thanks ... ohhh and whats a good powder to apply after this foundation its has to be good because i have a lil bit of acne too i dont want to break me! sooo can someone please tell a good powder for oily skin with acne thanks! :)♥♥