very simple 2d side scrolling collision data
hey everyone, I have a pretty simple question. I am making a very very simple game for my (highschool) programming class for my final project and I need some help with the collision data.
I know for a fact that I barely know enough to even begin a simple game, but I have to learn sometime. The game that I want is just a simple 2D side scroller where you control a character and he can shoot a gun or something of that sort at an enemy or two(haven't decided completely yet). What I have so far is a frame that has a background image on it of a simple level map. For now, I am using a ninja gaiden sprite from the NES just to test my manipulation of the sprite. I got it to move in the proper x,y coordinates using the arrow keys on the keyboard, but I need to know collision data. I want my sprite to stay on the 2D plain. I also need it so that if the character hits another enemy then it will detect some sort of collision. Character collision data and map collision data seems to be all that I need.
So far everything is very basic but I need to know this so that I can actually make my character shoot something and actually destroy it. Does anybody know any sort of method or anything that could help me with this? I just need a simple explanation or something because I don't even know where to start on this.
thank you for your time.

