If you want to include multiple mod files with GZDoom, select all of them with the CTRL key pressed and drag and drop all selected files onto the gzdoom.exe file.Drag and drop the Brutal Doom mod file (brutalv20.pk3 or similar) onto the gzdoom.exe file.Navigate to the GZDoom folder in Windows explorer (d:\games\gzdoom in this example).There are several ways to start Brutal Doom with the GZDoom source port. You can also check out the high resolution textures for ZDoom here.Copy the content of the downloaded zip file to your GZDoom folder, in this example you'll end up with d:\games\gzdoom\brutalv20.pk3.Doom II: copy DOOM2.WAD to the GZDoom folder, you'll end up with d:\games\gzdoom\DOOM2.WAD.