Check the preparation&installation note for things to do before the hackathon
After the project is defined and the team is complete, you can ask a coacher in the channel #qiskit-hackathon-bilbao-19 (qiskit.slack.com) to add the label group ready. This should happen before the group formation stage is finished. From this point on, you can use the issue to communicate progress as additional comments.
A Qiskit coach guides and advices the team in its project. Also will be your contact point after the hackathon, in case that the project have a continuation. The team needs a coach before the final submission at the end of the hackathon.