How to edit contract code


I’m wondering if it’s possible to edit the code of a contract created through the studio, or to pull that code into a custom contract.

Specifically, I’m interested having my NFTs on-chain, and I think I can follow the instructions here: Storing Data On-Chain - Manifold Docs
but I don’t know how to enter that code into the contract.

Perhaps it’s not possible to edit a contract created through the studio. I see there are some tools in the developer section and creator core, but I don’t really have any idea how to customize and deploy a contract using files from github. If there are tools or guides for that, I’d appreciate it and I can see if it’s within reason for me, otherwise I can just go with the out of the box option for now.

I tried searching, but wasn’t able to find an answer to this. Thanks so much for your help!