Installing games ALREADY on hard drive

Hi. I am…having trouble. I downloaded the games I needed to install during free high data month with Comcast, and again while I was reloading the computer. So, I already HAVE the install files on the hard drive, in media/e****/b7ac43e3-03d7-4af7-a5ad-f4eeaa2a600d, as well as an external. How do I install from THOSE files, and not redownload everything from GOG? Thank you.