The Guides for the Cloud Zoo (developer.rhino3d.com) are great for the technical information. They also have a code sample at github (flask/python) for the vendor server end.
I just went through the process of implementing Cloud Zoo licensing and would be happy to help others up the learning curve. There are two administrative steps with McNeel (api credentials and signing key) which you’d want to leave time for.
The technical docs are good; I had some things about how the actual vendor and user process worked to figure out. I wrote up a few and will write up a few more guides for this.
Noting @gustavo’s comment about making it easy for the end user:
There’s one hurdle that I have a request out to McNeel for which would make the user experience much easier: giving the userid to plugins so they can register a license in-program rather than forcing a new user to separately log into the McNeel site with their user account and figure out how to add a license.
WISH: Cloud Zoo Plugin, Provide User’s EntityID from RhinoCommon - Rhino Developer - McNeel Forum