I'm currently lvl 43 and i have watched lots of videos on other people playing SW:TOR and they all seam to have a macro system were they swich for example the numbers on the top macro bars to F1 F2 F3 and so on. But they put the numbers back on the lower macro bar. To be honest i have no idea what the real name of this is but if you don't understand me i'm talking about were you plase your skills and abilities wich u use in combat all the time?

Can someone please give me some info on how to use macro's?

There are no programmable macros in this game like in some other games. I think what you mean is key bindings. Press Esc and click preferences. On the very bottom of that window you can click onto the key bindings tab. The Quickslot option will let you scroll through and choose what keys you want to assign to additional slots in bars 1 through 4.

If you want to enable additional bars, go to your interface editor. Sorry, I've had these on since the beginning so I don't remember the exact steps.