Yeah under the hood is the fuse box and relays. You don't need a meter but one would help. On the fuse box lid it should say what each fuse is. Locate the horn one, pull it out and look to see if it is blown. The lid should also tell you what each relay is. If the fuse is good, check to see if the relay is bad by swapping it with the same size relay. Replace the one you swapped out if your horn works now.
The first is the fuse box. The second is the lid showing locations and the fuses and relays.