Call the dealer you bought it from, they should be able to talk you through it on the phone in 7 minutes while it does it's thing.
Too much typing to explain in full, but it is quite simple once you do it a few times....
Main Menu > Install Download > Then the tuner will tell you that tuning is installed, press Y to continue or N to return to stock.....
If you press N (as in No, which confuses some people) the tuner itself will guide you through the process.
Yes, it takes as long to return to stock as it did to originally load the tune.
If you do not successfully return to stock, you can vin lock the DL and will not be able to reload the tuning.
I recommend you contact the dealer you bought it from and get some assistance.