I would love to use the Real Time Collaboration feature of Jupyterlab, but the documentation at hand does not explain it very well (+further searches in the forum + GitHub issues did not help).
My Question:
What are the exact steps needed in order to set up Real Time Collaboration with JupyterLab? (from a new, clean environment without any modules)
This features sounds suuuuper exciting, so I would love to use it in the future for pair programming purposes. Thanks already in advance! 
If at this time, using it via MyBinder will suffice, you can follow along step-by-step guide by @firasm (a.k.a. Firas Moosvi) to making a new repo and adding the real time collaboration ability here. The animation at the bottom shows then how to share the URL and open a new connected instance.
If you prefer something closer to the classic look there is Retrolab.
Current JupyterLab running it here clearly illustrates the few necessary items very clearly.
Beyond including the --collaborative argument when running it local, I don’t know what it entails as far as opening up your system’s security/ports.