First, reach the game's folder. You can do that manually or you can do it via steam (right click on the game > properties > Local Files).
Now go to EtG_Data and then Managed.
Backup your Assembly-CSharp.dll file, you wanna get back to the vanilla in case something goes wrong.
Copy "Assembly-CSharp.dll" and "EparlanaModLoader.dll" into this folder.
Launch The game !