As you first un-box your new D-STAR radio, the first thing to do is to make sure that it works on FM. So program your favorite repeater and try it out for a little bit. Once you know your radio is working, then it is time to start thinking D-STAR.
Did it work?
Make a call on the repeater and see if anyone responds, that's a pretty good test. Don't expect to hear a kerchunk when you un-key, nor a courtesy beep. D-STAR repeater controllers don't work the same way that FM repeaters work.
If your repeater has a gateway and DStarMon running, then go to the Last Heard page of www.dstarusers.org and see if your call-sign appears. The site updates it's information quickly, so it only should take a few seconds to see your call. If you see it, then congratulations!