Unable to load maps to etrex20

[tdetrex20]

I just purchased my first hand held GPS, a etrex20. Of course the loaded Garmin map is useless. I read about this site and thought I would give it a try. I loaded Basecamp to my computer and then loaded a couple of topo maps and that worked fine. everything shows up in Basecamp. Then from Basecamp I installed a topo map to the GPS. It seemed to load fine. However when I tried to view it on the GPS there appears only the arrow, no map detail. I disabled the base map and had only the topo map enabled. After reading the forum I tried changing the topo file name to gmapsupp.ing. No difference. What am I doing wrong?

[Seldom]

Which map?  If "My Trails" you need to zoom in to around 7 miles and be close to a trail.  If any other topo, you need to be in the area of the topo or pan to it.

[tdetrex20]

Thanks for the help Seldom, your solution worked. I didn't realize the topo maps required the base map to be running.