In the basic game you can have just one model of Officer rank.
You got the Domination correctly.
Command points - in the beginning of the game you calculate your permanent CMD-point pool (just add up all the CMD values in your force). At the start of every turn, you get temporary CMD-points equal to the value of your permanent CMD-pool.
When you use an order that uses up temporary CMD-points, you subtract them from the temporary pool.
When you use an order that uses up permanent CMD-points, both, your temporary and your permanent pools lose the amount of points that the order costs. So at the start of your next turn you get fewer temporary points when they fill up again. If you don't have enough temporary
and permanent points to use a given order, you can't use it.
Last, when a model of yours dies, check if it had a CMD value. If it had, subtract that amount from your permanent CMD-points.
Hopefully that was of help
Edit: Me is slooooow.