A lot of useful information about the tool can be found here:
000 - GitLab - where to look for the info
005 - PSNC GitLab - general information on how to use GitLab at PSNC
How to request Gitlab project?
How I can import repository?
PSNC GitLab - project migration
How to integrate your project with GitLab?
GitLab - just boring codes?
Not only! Meet: