Hello from Alberta!

Check your battery cables , cable connections, and the connection from the starter case to the aluminum BH, and back to the battery; the clicking means that the relay is working on the signal side.
The quickest way to prove the starter is Ok, is to jumper across from the power-stud to the starter signal wire, (brown IIRC).
If it cranks, then the problem is between the starter and the ignition switch, which puts the relay right in the thick of it.
IMO the factory relay is pretty robust; mine was already ancient when I bolted it on in 1999. I think it might be an original 1968 model. The newest it can be is a 1975..