Search: "auto landing"  "Auto pilot approach"  etc.

There are prob several dozen threads on that topic..OR take my humble  advice 

If you already understand the A/P function,, and can land by hand,,, just set up the same approach (try to come in a little under the glidescope) and when the needles start to center,,, click "Alt", Spd" and "Hdg"  OFF, then quickly click "Apr"  ON

All you have to do is watch your speed and deploy the flaps and gear,,,then  click the A/P OFF altogether and flare a bit just over the runway..   


good luck..