You can download the files on the Releases page!
On Steam, open the game's properties then under "Local Files" press "Browse..."
Inside of the Risk of Rain 2 folder, drag/drop the "Risk of Rain 2_Data" folder from inside of this zip into the "Risk of Rain 2" folder you should be currently in. Press "Yes" if it asks if you want to replace any files.
In game, under your profile in the top corner is a drop-down for languages. It should now be set to "English (ItsZen_EXE)" :)
To disable the mod, you will need to verify the game's files through steam.
This mod will break every single update! so be patient when an update comes out for more info, or redownload the mod to reinstall it!