Hi Pus..with this SRTM stuff there is no need to select anything......it merely gives you more detailed terrain ie higher hills etc....not such a flat looking landscape. Just go to the area you have added and look around and compare it with the default terrain. The readme seems ok apart from the TYPE IN A Scenery title. That should be filled in automatically when you select the area you browsed to.....just click ok then restart the sim. If you have done it correctly there will be a RED message telling you to restart the sim.
.....you can put all your downloaded areas into this same folder and then once the path is established they will show up in the sim as you fly.....or as I do instead of making it as your example SRTM-NA, I put each area into a seperate folder like SRTM GBSOUTH or SRTM Switzerland etc....you will have to ADD EACH area seperately that way but at least it helps to keep track of what you have..........hope this helps..commoner

BTW adding airports etc is where you have to start selecting the scenery

"In theory, there is no difference between theory and practice. But, in practice, there is."