Where the heck can I find a file? (details inside)

[armyturtle77]

I installed CasaOS on top of Xubuntu. I really like how CasaOS looks and feels. I've got DNS-updater working, Crafty (a minecraft server), and Dozzle (logs) running. I updated so I also have the Big-Bear repository/store to choose "apps" from. Then I tried to install Immich. I love this photo app. It's running currently really well on docker on my Windows 11 machine - but I don't want to leave that machine on all the time. So I installed Immich from the Big-Bear store on CasaOS. It's running. I've uploaded a single photo to test. However I want to run Immich so that it stores the pictures and videos on an external USB hard drive I have installed/attached. To do so, I need to update the ".env" file for immich (according to immich tech people). But I have no idea where to find this file since I've installed immich with CasaOS. Inside AppData folder I have big-bear-immich folder. Inside that folder I have 3 folders: model-cache, pgdata, & upload. Inside all of these folders I cannot find the .env folder.
On my windows 11 machine I have an immich folder flat, which contains the .env file starring at me along with docker-compose.ml & a library folder, and postgres folder.
Any help is greatly appreciated as I really like CasaOS.