I need help with camera mode and rendering...

So basically I’m brand new to this program and I started making an animation. My problem is that I didn’t know my drawing should fit into the camera, so I randomly started making a drawing on the drawing panel and when I tried to export it, it was just a black screen. After a little research, I realized my drawing should be in the camera panel, but now I’ve stuck with a drawing much bigger than my camera and I don’t know how to make the drawing proportionally smaller or how to make the camera bigger. Also when I’m in camera mode my drawing is black and white. Please consider helping me if you can. Thank you.