Hola my friend virus. This time you beat records with that bad english . I'm not sure I understood what you said. I'll try to answer anyway .
You can assign units to the command turret much like you can assign units to a sensor. The commander give a bonus to his unit and manage the repair of his units by itself. You move the commander and the units follow him and attack where you asked him.
The "shift+1" key select the commander. Just like if you created a group with "ctrl+1" and than select it with "1". It's pretty useful once you start to use commanders.
Not automatic repairs, I'm afraid. I think what Iluvalar meant was units under a commander's control are able to automatically go to a repair facility if they are damaged. once repaired at a repair facility, they will drive themselves back to the commanders side.
But Commanders do give the following bonuses to the units attached to it: Accuracy- Speed - (Negative to) enemy accuracy - damage taken.