Sign-up for the profile you associate most with and think you will contribute the most as during the Climathon.
See if you can fit another profile. If not please send the local organiser a message (next step) and they will see what they can do for you.
You will be able to participate in the Climathon as a team and work together with people you know on the Climathon challenge. If you register as a team, please make sure that you list all team members in your application at the relevant question. Team members will have to register themselves though to secure a place to participate in the Climathon.
You will be able to either join a team during the Climathon or work with a new team that will be formed during the first hours of the Climathon.