zoom out

I am really new at this so just bear with me.
When i start a window, the coordinates go from -2 to 2 for x and y. what is the best way to change this?

Use the gluLookAt function.

gluLookAt(
eye_x, eye_y, eye_z,
at_x, at_y, at_z,
up_x, up_y, up_z);

up
|
|
at---------------- eye

Or simply just translate into the screen:
glTranslatef(0.0f,0.0f,-10.0f);