Games without connected player clients

I'm considering getting the Fantasy Grounds Ultimate Edition to move my current gaming group onto a virtual tabletop since with travel and obligations it's hard for us to meet in person consistently. However, I'm concerned about the learning curve of the app and how well it will accommodate some of our house rules. Is it possible to setup a game as just the GM with no connected players where the GM takes all player actions? Sort of like a test mode or something like that? I assume there is, but I haven't seen any direct references to it.

Yes, you start a second instance of FG and connect to your first instance using "localhost".

You can run a GM instance and not have any player connect. You can setup the PCs and NPCs etc.. Is this your end goal for gaming, or is it just for you trying out the product?

The free demo version of the software also allows you to do this. So you can try things before you buy.