Boiii.exe is the client, just copy the exe to the root folder of the game and play.
t7_dlc.torrent is the dlc. you will need this if you don't have it.
t7_full_game.torrent is the full game you can use this as the private version has no steam check.
Make a backup of this as it might get removed.
This is the link to the download from the xlabs website. (The orignal download) https://updater.xlabs.dev/boiii/boiii.exe