The Legend of Zelda: Majora's Mask Walkthrough

Majora's Mask p.10

Bomber's Code
Back outside (North Clock Town), you will notice Tingle is now floating around with a red balloon. He'll be that way from now on, so if you didn't already purchase a map of Clock Town from him, shoot down his balloon and do so. In the center of this area is a kid wearing a red cap who's shooting at a Majora's Mask balloon. Why does it even have that symbol on it? If you speak with him, he'll tell you to go away. He does mention, however, that if you can manage to pop his balloon, well, maybe you'll be worth his time. Sounds easy enough.

Face towards the balloon, press B to enter a first person perspective, aim up at the balloon and charge up a bubble (to give it further range). Release it before your bubble pops and you should easily be able to pop the balloon. This will startle the kid, who is now eligible for conversation. Go talk to him and he will tell you how impressive your big head is. Apparently, he is willing to let you into his gang, which grants you access to the Observatory. Hey, that's where the Great Fairy told us to go! The only catch is, first you will play hide-and-go-seek with him and his friends. Sounds good, right? You have until the next day starts, so if it's night already, you'll have less time to do it.

The kids will run off and hide now, and it's your job to find them. They cheat however, and run away when they see you. So it's actually more of "hide-and-go-catch." Put your Deku skills to use and use A to spin after them and B to shoot bubbles and stun them temporarily.
one Bomber in each of the five locations within Clock Town:

North Clock Town - At the northeast corner
East Clock Town - Near the bell at the higher level of the Stock Pot Inn. Use the Deku Flower to launch yourself up there.
South Clock Town - Hiding inside a crate right in the center of the area.
Laundry Pool - Hiding inside a crate near the water.
West Clock Town - Walking around in the higher part of the area.
After you have caught all of the children, the screen will fade and you'll be back in North Clock Town. Well, they've decided you can't actually join the club! BUT, they will give you their password to let you go to their secret hang out spot in the Observatory. Nifty! It is stored in your Bomber's notebook. The order they are standing in is always different. All five are shuffled around each time you play, meaning there are 120 possible combinations for this password and it is completely random. For a little while, you can talk to the kids and they will tell it to you again in case you didn't write it down. After that, if you ever forget it, you can always play this little game with the kiddos another time.