A Job Type bundles the master templates used for a kind of work (e.g. Shed Home = PO + Quote + BOM). When you activate a customer, the bundle's templates are forked into that job. Templates are referenced by pointer — a shared template (e.g. BOM) can live in many types.
Tick the master templates this job type starts with. Manage the masters themselves in Templates.
A hint recorded with each job for provenance — the .skp you Save As when selling this type. (Just the filename; the plugin doesn't open it.)