Open up the screw terminals of the new relay fully, so you can fit the wires in without fraying - or fit the new ferrules.

Insert the wires into the terminals per the large silkscreen text adjacent to the terminals (note the red/black don't match the small wires).

Again, note the direction of the large current sensor around the red line - go back and check your notes if it matches your original.

Using a medium-large flat blade screwdriver, practice Turbo Gorilla Grip on all 4 screw terminals. Tighten it almost 'til you think it'll break, then a little further. Screw it back and forth a couple times and see if you can get even more crush out of it. The goal is to fully flatten the strands so it won't settle in the future.

(This is less important if you've added ferrules, which already provide a good amount of crush to the wires! But still, give 'er a good crank!)