I always suggest training, try and get instructor led training if you can, and if not get hold of the training manuals together with the NAV demo system and go through them yourself, some clients depending on the Microsoft agreement can access the training on the Microsoft site, alternatively your partner can get the manuals for you
The training manuals examples all tie back to the NAV demo system and your partner can load the demo onto a PC as a standalone to work on
Cheers
Nev