TableGen is a DSL (Domain Specific Language) that powers various critical components in LLVM: instruction table, disassembler, and driver option parser, to name a few. While there are many learning resources in the wild that teach people how to write TableGen code, there aren't many places talking about developing a TableGen backend -- the key component that translates TableGen code into other formats like header files. In this tutorial, we are going to show the audience how to write a TableGen backend that can translate custom TableGen records into desired formats. At the end of this tutorial, we hope the audience can have a deeper understanding of the TableGen infrastructure and have the skills to implement their own TableGen workflow.