Mnemonic Seed Phrase Creation Program

I am trying to understand the code for producing a Mnemonic Seed Phrase in the BIP39 standard. I need someone to look at the tool I am using and dig into the code and pull out the parts that are necessary to run this function. I want to replicate this tool in my own version of Python code. I need someone who is a coding expert and knows something about cryptography so they can explain how I replicate this process on my own using python code. Ideally I would like them to send me a working program in Python for this process. I would also like them to take me through the code, step by step to understand how this was achieved. I know a bit about coding and python, but I am not an expert. I need someone who is smart and who would be willing to setup some calls on zoom to go over the code once they have it working.

https://iancoleman.io/bip39/