Inside the mini junction box on the Dayton motor for my whole house
fan there are two types of connectors. One is a nut on a post. The
other is a spade lug. There is a knockout for a cable clamp.

How do I connect to these? Do I crimp the appropriate connectors onto
the wires in NM cable? For crimping connectors onto wire, it seems
like flexible wire would be better - not the solid wire in NM.

Thanks for any help.