We spent a lot of time looking at projectiles and projectile problems in class so this should be a concept that you are comfortable with. If you are still a little unsure, there is a good summary page here. The page contains interactive questions to check your progress – just make your selections and press the green “=” symbol each time to find out if you were right.
Here is another site with a decent summary. It has a flash animation showing how motion in the x and y directions are treated independently and explains the method to solve projectile questions.