Re: Pictures.
You either need to use img / img and post a link to a picture URL OR, click on the "additional options" at the bottom of the "full reply" or "new post" window and you can add up to 2 pics. Once you open addn'l options, it's pretty obvious.
Re: Trackball. The trackball probably has 2 sets of wires / connectors coming out of it with 4 wires / connectors in each set. OR 1 big set with 6- 8 wires / connectors.
There are 2 axes on a trackball, one for x and one for y (horizontal / vertical) Each axis has a ground, 5v, x1, x2 (or y1, y2) those correspond to the screw terminals on an optipac. You run 1 wire from the each of those connectors to the corrsponding terminal on the optipac. You will have to figure out which wire goes to what. Posting pics, or providing more information about the specific trackball will go a long way, however.