Hey man! A couple of things to watch out for here to make sure you get this wired up safely.
Each MotoHorn compressor draws about 20 amps, which means two of them will pull a combined 40 amps. Because of that, you have to be careful with where you run those 12-gauge wires:
If you are using the relays properly: The thick 12-gauge wires (Pin 30 on the relays) are meant to handle the heavy electrical load and should be wired directly to the truck's battery. The upfitter switch is only meant to trigger the relays. To do this, you would "Y" the two thinner trigger wires (Pin 86 on the relays) together and connect that single wire to your upfitter switch.
If you are bypassing the battery and powering them directly from the upfitter: You can "Y" the two 12-gauge wires together, but you must connect them to a 40-amp upfitter switch (on a 2024 Super Duty, this is usually Aux 5 or Aux 6). If you use Switches 1-4 (which are typically 25A), both horns going off at once will pop the fuse instantly.
Ford likes to change wire colors like the weather, but the positive wire running directly to the horns (located right behind the grille) is historically Yellow with a Green stripe.
However, to be 100% sure on a '24, the safest bet is to unplug the connector right at the factory horn, hook up a multimeter or test light, and have someone hit the steering wheel horn button. Whichever wire lights up with 12V+ is your positive—that's the one you cut to run to your relay trigger.
Hope this helps and gets the ladies all horny

.