Gitlab Training

I am looking for recommendations for online training resources for GitLab. Preferably looking for free, self-paced courses but would entertain other options.

GitLab is a specific implementation of the git protocol.
You may want to start with an Introduction to Git - Training | Microsoft Learn

And then move on to more specific GitLab content.
They have several tutorials available. Learn GitLab with tutorials | GitLab

GitLab themselves offer PAID training via their own Learn portal GitLab Learn | GitLab