You help them with the tooling. You will also need to say "because, magic" far more often then with most projects, but if you have someone who knows what they are doing walk you through the difficult, boilerplate type, parts, then modding minecraft is generally not exceptionally difficult. The other risk you have is the chance that they will want to interact with some less explored part of the code, in which case the problem goes from boilerplate/tooling difficult to normal difficult.

Probably the best way to go about it is create a dumbed down interface for them to work with. When they inevitably want to go outside of what you wrapped, you can either wrap the additional functionality they need, or show them how to use the underlying API.