I've got the horn.
I've got the horn button.

What do I need to wire it?
Relay suggestion?
Wire gages?
Inline fuse?

Thank you.

Stock setup? Aftermarket parts? Where do you want to put the horn button or horn? Some more information about why you need this info and how it's different from the original setup if it is, etc. would help a lot towards getting some help to you.
What you are putting this on? Year, model, make of car. Give us something here

Good questions, Henry. Thank you.

1988 Iroc-Z
Original horns.
Horn button location in dash - where cigarette lighter was previously.
CAN NOT use steering wheel horn "button"; nor column wiring.


So... wiring from the button to a new relay...and battery... and horns.
Do not need to go through fuse box; can use in-line fuse if easier.

Chuck

Google auto horn wiring and get tons of layouts that will all work fine