After I got the horizon, I went through the manual page by page and tried everything that was shown. It's not the best manual, but it helped me get familiar with the machine.
If this doesn't help, lug the machine back to the dealer and get some help. The Yahoo group is great but you might find greater benefit in one on one, face to face assistance.
A lot of dealers will also provide help with questions over the phone, particularly if you live a distance.
Finally, maybe the machine just isn't for you. But you won't know until you've gotten some assitance with it.
Good luck.