Would there be an simple example of how to add a new target machine and compile the relative assembly in LLVM?

Question

I'm learning LLVM and would like to add a new target machine with its own set of instructions into LLVM.

I'm reading the documentation, but it is complicated. Thus, I would like to ask if there is a simple example of how to do this?? And how to use the new compiler to compile a simple C program.

Thanks a lot!