I tried following both of the tutorials and with both methods I get this error when I try to launch the BAT file. I own the game on steam and had steam open while trying to run the file. I uninstalled and reinstalled both the game and the file packs. I don't know what to do.

You need to own Half-Life 1 on Steam

Well now I feel dumb. One of the comments said I need to own "the game" and assumed that meant opposing force. Please excuse my stupidity

If it makes you feel better, you are not the first to assume this. Logically, you should only need to own Opposing Force and that's how Blue Shift works as well. I think it's a mistake with how the package is set up but I don't know how to fix it. Maybe someone like @hobokenhoboken would know.

This probably wouldn't work, but you could try adding an additional entry in the liblist.gam file located in "Half-Life\gearbox_WON":

fallback_dir "gearbox"

That didn't work either. Still, I appreciate the effort to try and fix it