Simple texture painting problem

I’m designing an avatar for a friend’s game and I’ve spent several hours trying to figure out how to paint an eye onto a sphere. All I can find on the subject are 40 minute tutorials on Blender paint from version 2.4 - 2.7 that skip several steps in the current release. I cant seem to figure it out on my own. How do i go about painting 3 distinct circles on a sphere? My goal is for the eye to look like this

Thanks for the consideration and any help you can give.

Have your eye image, sphere (Cube with Subsurf lvl 2 Applied; To Sphere, 1 in edit mode herein example) unwrapped and texture to paint on ready (toolshelf will have option Add on Slots tab). Choose your image as a paint texture for the brush and set Brush Mapping to Stencil.
Position and scale stencil and Sphere using mouse buttons and Shift, Ctrl, Alt, then paint.

Well mainly i just want to overlay 3 circles of pure color to form an eye. Just like this:

I’m finding it difficult to find a tutorial that simple that is also for the current release of blender. I’m filling in the skipped steps as best i can, but i cant manage to do it.

Here is my model so far.

For painting circles you could just use the anchored stroke

Or use a circle brush texture

Thanks Richard. That technique really helped once i figured out the basics of texture mapping.