When you create your project, add people you've been working with your idea on. They need to be members of the platform for you to add them to the project (if they aren't now, you can always add them to the project later). To do this, type the @ sign in the Instigators section of the Project Builder and start typing the name of your team members to find them on the Digital Makerspace. Remember that anyone you add as a fellow instigator will also be associated with the intellectual property of that project.
If you need to add others, go to the Tag Browser, under Topics, and look for the skills you need. Click on each Skill Tag to view a list of users who have included those skills on their profile.
Lastly - if someone asks to join your project that you don't know ー before accepting the request, look at their profile, and chat with them on the in-system message service to find out if and how they could contribute and what their motivations are. Remember you always have a right not to honor their request.