Sorry there isn't really a tutorial.
I think you are right and the Visual Studio support, the projects, may be incomplete. This is a fairly old personal project and hasn't received the maintenance it deserves. The code is all there, but not the project files, perhaps, unfortunately.
One approach would be to use some sort of XML to JSON converter, and then load the JSON into mongodb, which can be done via many tools (command line utilities, MongoDB Compass iirc, etc.). You might search for "xml to bson" on stackoverflow and quora for some ideas.
It would be important to make sure the XML loaded, the schema makes sense. In some cases , given XML is "documents", it may make a lot of sense in MongoDB in a straight translation. However in other cases, a different schema may be better (i.e. maybe more than one collection depends what the XML is). I believe you can find some information on MongoDB schema design at MongoDB University website (free courses and such there).