Map question for eTrex 20

[ColdTracker]

 New to the forum. A lot of good imformation here.
I have a new eTrex 20 version 2.80. I have BirdsEye Topo loaded on a SD card in the GPS and would like to add more maps (gpsfiledepot mi topo and maybe a OSM map). I have read through the forums about changing the name of the map and using .img on the end. I go into the garmin folder but can't find gmapsupp.img. Is this because all I have in the GPS is BirdsEye Topo wich is a .jnx file? So if I load another map it would be the first map with gmapsupp.img in the garmin folder? Then change the name of the map using .img on the end then load another map and do the same?
I am just worried about over writing the BirdsEye Topo map.
                                                                                                    Thanks

[Boyd]

Birdseye files are completely different - .jnx as you have noted. None of Garmin's software will overwrite them, so no worries. If you use the current version of Basecamp and MapInstall, then you don't have to worry about filenames with any maps. It will assign unique names to each map that you send to your eTrex. The trick with renaming gmapsupp.img is only needed if you use Mapsource, which is older discontinued software.

[ColdTracker]

Thanks Boyd and all the other contributors on this forum. With garmins lack of instruction this makes the learning curve alot easier.