1) Is the click you are hearing from the starting circuit (ckt) cutoff relay? Or from the starter relay (as labeled below)?
2) Can you jump the starter relay to get the starter to spin? That should prove out the starter itself as being good as well as sufficient battery power to spin the starter.
3) If the starter and battery prove good, then I'd prove out the starter relay (with jumper wires from + to L/W and ground to R/W on the trigger terminals). You should test the starter relay by itself as there's always the chance the starting circuit cutoff relay (upstream of the starter relay) is clicking but not actually connecting terminals internally.
4) If starter relay is good then you end up at the starting circuit cutoff relay.
5) Just in case, is the kill switch in the ON/RUN position?