There are three main community spaces for the Wonderful toolchain:
For asking questions and longer-form discussion, a good place to start is the forum thread on NESdev. With enough activity, it might become a subforum!
For discussions and banter, we have a Discord server, at least for now. (An IRC bridge may be provided in the future, if user demand exists.)
To report bugs and feature requests, use the issue tracker on GitHub. Feel free to consult first if you're not certain whether what you're observing is a bug, or if a feature is not already present.
Advice
Each community is governed by its respective rules. However, some general advice applies to all Wonderful Toolchain-related discussion:
Don't be afraid to ask questions! It's better to ask five questions too many than spend a day frustrated and confused. In addition, it is an useful signal to maintainers: the necessity of asking a question, for something that is not already documented, can suggest that some information is missing or that it is not explained adequately enough.