Install MO2 for FO3 Help!

[chucksteel]

I recently picked up a Steam Deck to use as my gaming system. (don't judge please it's much better then the way I was gaming with an emulated version of windows 11 on my Mac.)

I was following the tutorial from "MO2 Linux Installer" I was able to install MO2 for both FO4 and FNV with out any problems but I'm having a bit of an issue installing MO2 for FO3.

I get an error saying,

Downloads: install.sh - Konsole
New Tab, I Split View ~
L Copy
Paste
Q Find :
INFO: all dependencies met
INFO: selected game 'fallout3_goty'
INFO: found Steam in •/home/deck/. local/share/Steam'
INFO: game not found in '/home/deck/. local/share/Steam•
INFO: game not found in '/run/media/deck/Itb CF Drive'
INFO: steam not found in •/home/deck/.var/app/com.valvesoftware.Steam/. local/share/Steam
ERROR: could not find any Steam library containing a game with appid '22370'. If you known exactly where the l ibrary is, you can specify it using the environment variable STEAM_LIBRARY
The game is installed on my internal SSD and not on the 1TB CF drive. I don't have a clue on this part "If you known exactly where the l ibrary is, you can specify it using the environment variable STEAM_LIBRARY"

I do know where the game is installed.

I did do some Googling on the interwebs and one suggestion was to check that "Protontricks" could see the game and it did.

I'm at a loss of where to go from here and I do hope someone here can point me in the right direction or lend a helping hand.

I do apologize, I have no clue on how to add links or images here.

thanks in advance

chuck

[FlavoryCheese]

I really need an answer to this.... someone said to change the environment variable in another post, but no one will say how to do it. I'm new to playing on steam deck so you'll have to be specific

[WarnerCK]

I haven't played that game, nor fiddled with external mod managers, but an environment variable is just a string that you can declare, and that programs that are interested can look for. If you just want to set an environment variable as a one-off when you run something you can just write it as a key value pair (env vars are customarily in all caps) like so: "FOO=bar blah" where "FOO" is the environment variable that you want to set to value "bar" for the executable "blah."

Note that in Steam %command% is used as a placeholder for "the thing you normally run," so in Steam you can set FOO=bar %command% in a game's Properties to apply an environment variable to a game in Steam.