OpenGL is an interface for the video card - so calling opengl functions is the way that you ask the video card to draw stuff - you aren't actually "drawing" anything yourself - you provide opengl with the data by calling functions and then you have it draw using that data by again calling functions

Okay, and what if I wanted to "draw" characters? Would I have to be able to determine a bunch of coordinates, height, width, etc. for each character I want designed?

You would draw your character sprite sheets (assuming you are talking 2d here) on regular image formats - png, jpg, whatever - then you would render those images on to quads which will have dimensions determined by the vertices that make up the quad.. a quad consists of 2 triangles which is 6 vertices..

The process of drawing the quad and rendering a loaded texture to that quad is different if you are using shaders or not - it is at least a few pages to describe these processes but there should be plenty of tutorials on how to do this using java/opengl

basically your characters would be sections of a sprite sheet texture rendered on to the quad - you can transform this quad around the screen and cycle through your sprite sheet to animate the character

Okay, thank you. I will definitely have to do more research on that topic. But your explanation did help me understand the concept.