Learning about compiler theory and how it would relate to the process of writing a decompiler!
Following this guide for the general process, which is broken into steps without code for how to parse C into assembly: https://norasandler.com/2017/11/29/Write-a-Compiler.html
Its about as easy as it gets - clone the repo, compile it with 'make', and run the program with:
./compiler <file to compile>
Once the .s file is generated, use gcc to assemble and link the .s file. (gcc -m32 <.s file> -o <executable name> )