Any good beginner tutorials for learning LLVM
As stated in Buffy's answer, you'll want to first be familiar with the other steps of compilation, because code generation is typically the last step in the compiler pipeline. If you haven't already, I'd suggest looking in to lexing and parsing as well. Optimization is nice as a bonus, but llvm does a good deal of optimization on its IR by itself.
Once you're familiar with the general outline of how a compiler works, you can start building one yourself. There is a language that is designed to be easy to build a llvm compiler for, called Kaleidoscope, and I'd recommend looking up a tutorial for building a Kaleidoscope compiler in whatever language you choose. llvm has bindings to many different languages ranging from haskell to C, although you will likely have the best experience learning in C++ since that's how llvm's API is implemented.