Managing GitLab Projects
Unlike GitHub, GitLab lets you manage your projects (GitLab’s term for GitLab “repos”), under free groups and subgroups (GitLab’s term for GitHub “organizations”). This allows a superior level of organization and more precise control of access, sharing, and visibility.
You should Creating a Custom Domain Web Site before continuing. It will walk you through creating your first GitLab group matching your Good-to-Gig custom domain.
After that all you need to do is create subgroups and projects within these subgroups.