Hi there. I'm a noobie here so be patient with me.
I just downloaded the windows 10 Doom BFG ver. but can't instal it. It is on a SSD not the primary or recomended drive. The play buttom won't light uup and np icon on the display. The file is on the drive but it won't play. What can I do?

I dunno. Try using one of the alternative DOOM source ports.

Did you download the "Offline Backup Game Installer" (= under the Galaxy installer in your account)?

If so, you should have one .exe file and one or more .bin files. You have to doubleclick on the .exe file...that should start the installation process.
After the installation is finished, there is a "start now" button (or smth. similar), that you press. Then the game should start. There can't be any "play" button, until you installed the game (not via offline installers, anyway - Galaxy may differ).

Thanks guys. That was very helpful.