I am attempting to learn how to create rust plugins, I know c# pretty well and I know a little of how plugin hooks are called, but the issue im having is where everything else comes from and if there are other apis or documents that I have not easily found

Rust doesn't have public APIs. What all plugin developers do is just decompile and read the server DLLs. Just install a Rust dedicated server on your development machine via Steam CMD or other tool, then install Oxide on top of it (download and extract over your installation), then open Assembly-CSharp.dll on a decompiler such as ILSpy or DnSpy. Most Rust classes are in the global namespace. There are some other used DLLs but they will usually get loaded automatically when you are browsing the main classes.

When you want to develop something, the process is usually to start with identifying what classes correspond to the objects you care about, then looking through the code to figure out how you want to interact, such as by modifying properties or hooking methods. You will see the Oxide hook calls right there in the assembly when reading the methods, so you will know immediately whether a hook exists for your use case without reading any hook documentation.