I cannot find any implementations of a class that extends uvm_reg_file

I am trying to create the DPCD registers within the DisplayPort standard, and it’s divided into fields each consisting of 256, 8 bit registers. So I wanted to place each of those fields in a register file and instantiate all of them into a register block. I just can’t seem to find an implementation of a register file anywhere online not on GitHub or any other site I just want some sense of whether what I am writing is right or not as I am only going on from the UVM reference manual and the user guide, and I don’t know if I am missing something. I have some question marks about the address mapping as to not do something that should be done in a register block.

Check out the following chapter and its section in uvm cookbook Register Abstraction Layer you will find answers to your doubts/questions.
Here is a link to the full example SPI master testbench

Also, I find this tutorial very helpful Candy lovers RAL