What are these parts & how do I test them?

The remaining wire goes to your CLUTCH SAFETY SWITCH so the clutch must be in when cranking. Remove that wire and hook a jumper from that relay terminal to ground. See if the engine now cranks with the key.

Engine turns over but only by jumping the starter relay.

Hooked a jumper from CLUTCH SAFETY SWITCH to ground and turned the key. Still nothing,