This is a work in progress documentation, not everything is documented here, but because Barotrauma classes are exposed to Lua, you can check the Barotrauma source code for functions and fields that you can access.
Downloading and using the Core Content Package from Workshop should be enough to have it installed, but if you want to install it manually, you can check out this guide.
If you want to get started with Lua For Barotrauma modding, check out this guide.