Note: @mentioning a boombox user in a comment on an audio file will automatically invite them to collaborate on a project.
To manually add users, click the "projects" tab in the right side navigation, then select the project for which you're looking to invite collaborators. (To discover and connect with brand new collaborators, check out our Network.)
Under the "collaborators" tab, click the "invite collaborator" button in the top right. Type in their email address and dial in their access level & role. If you already know the splits they'll receive, you can set those from this window as well. You do not have to add splits at this time. You will be able to access or adjust them any time you want.
Once that's done, click the "save" button and they'll be sent a request to join the project.