A beginner to hackathons. Can someone guide me?

I apologise in advance if this is not appropriate for this sub.But since Kochi is filled with techies,I thought someone could help me out. I'm a BTech first year under KTU studying in a college in Kochi and I have registered for a hackathon which is claimed as beginner - friendly. Regarding my coding knowledge,I just have a basic idea about python and that's about it. Can someone who has participated in hackathons guide me on what kind of an idea to pitch , how to approach it and a general format of such a hackathon? It would be really appreciated. I just need a general understanding about the whole thing.