This site is the CodeRefinery manual, which explains all about how we work. It has both introductory material for new people and reference for those already taking part.
Read it online at https://coderefinery.github.io/manuals/.
Related is Train the Trainer at https://coderefinery.github.io/train-the-trainer/, which is more about learning how to teach.
For the most part see the manuals themselves to learn how to contribute. The manuals are built the exact same way as all other CodeRefinery lessons, and contributions are similar. We welcome contributions, but since this explains what we actually do, it's best to get involved and then propose new ideas.
By now it's pretty stable and realistic about what happens.
CC-BY, see <LICENSE.md>