Has anyone installed the H2 database on the Thingworx platform? There are no instructions in the 8 installation manual

Ray, if you get the get the H2 version of ThingWorx, the database comes with it pre-packaged. All you would need is to just deploy the .war file; provided you follow the other parts in the manual like setting up the ThingworxPlatform folder, adding the license file etc. You don't have to do any configurations or connections from a DB perspective.

I would like to recommend you to read the following article:

Comparison of ThingWorx Database Options (taken from KCS Article CS257403)

It describes different ways to use databases with Thingworx