For questions concerning the mathematical software system SageMath.

SageMath is a free open-source mathematics software system licensed under the GPL. It combines the power of many existing open-source packages into a common Python-based interface.

StackOverflow has a fairly heavily used [sage] tag as well for more programming-related question, with more links; see also the [sage] tag on MathOverflow.

Note also that Ask Sage, SageMath's questions-and-answers site, and sage-support, the user support mailing list, are very active and that questions asked there typically get answered faster than on the StackExchange network.

You can also look at the official documentation of SageMath.