You have the large cable from the Battery to the armature. Then the 14 gauge from ignition switch to the relay. No fuse link needed. You put inline fuse holder socket with 15 amp fuse in the wire going to the relay.
Check out posting from Davenz. He asked similar questions.
Are you running headers?
Heat Blanket for starter?
Edit: the "relay" is the "S" on the solenoid. The solenoid is a relay... Small amperage input closes contacts, allow high amperage to flow to the brushes and energize windings... Causes motor to spin and Bendix pops out the starter gear, meshes with flex plate/fly wheel... Engine turns. Very simple system.