I did the guides to help and be used by as many people as possible. It's a no brainer to write about them here, so they can be found easily
Text find and Script dump
https://romhackplaza.org/documents/romh ... criptdump/
Font and graphics extraction-insertion (when there is no compression involved)
https://romhackplaza.org/documents/romh ... ntsprites/
Text and Script insertion
https://romhackplaza.org/documents/romh ... insertion/
Compressed graphics
This is more of an Intermediate topic, but it is explained as easy as possible. So, you can use it even for your first project.
https://romhackplaza.org/documents/romh ... scheme-re/
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These guides are by no means the only way to do this, but they should explain the basic and easiest way to do it. With display of the very basic concepts and item labels for you to find anything if you want to dive deeper.