If disabled, your custom configurations will not appear in the vehicle selector. (They will be only accessible via the Parts Selector > Save/Load menu)
What file did you want again? --- Post updated --- In my files, I only have my configurations as pc files. What do I do to make them accessible in-game?
Nothing, I just don't know how to get the green install button. I know I can do it the manual way. Let's say the h series bomb. https://www.beamng.com/resources/deathmyself-bomb-for-the-h-series.1914/
Go to Documents/BeamNG.Drive/vehicles and send me every .pc file you see. So that I can see if your configuration are actually broken or it's just a problem on your side. You may need to ZIP them, as the forum may not accept .pc files for attachments.
I made a configuration, found the file location and drag and dropped the pc files of the configs I wanted where the newly created config file location is.