vCAC REST API - Where do I start to request a new machine?

I'm poking around in C# looking to create a machine request programaticly.

I've got the context to ManagementModelEntities and wanted to know am I creating a VirtualMachine object or am I creating a Request object and then invoking the appropriate context.AddToRequests() method... what is required? Without examples or thorough documentation this is becoming quite frustrating.