Ocarina of Time Big Poe Guide
The Legend of Zelda: Ocarina of Time has four Bottles that Link can acquire. One of which can only be acquired after finding, defeating, and collect all 10 of the Big Poes found in Hyrule Field. In order to complete this quest, you first need to complete the Epona side quest, as well as acquire the Fairy Bow from the Forest Temple.
When you first entered the Castle Market as a child, the first door on the right led to the guardhouse. Once Link becomes an adult, this has turned into the Ghost Shop. It is run by the Poe Collector, a gangly, one eyed, hooded figure with a stick. He loves the spirits formed from the hatred in the world known as Poes. You can bring him smaller Poes that you collect from the Kakariko Village Graveyard to earn some rupees, but the main reward requires you to find the 10 Big Poes. Each one you collect earns you 50 rupees. If you catch them all, you'll be rewarded with an empty bottle.
The 10 Big Poes will only appear when you pass over specific locations in Hyrule Field. It's generally just a small ring on the ground that once you enter, the Big Poes will appear in front of where you're facing. By running through these invisible rings on Epona, you can whip out your Fairy Bow and shoot them as they run away from you. Two hits and they'll fall down. Speak with them to put them in a bottle. You'll have to bring them back to the Poe Shop repeatedly, seeing as you only have at most, three bottles. While the Big Poes are in small rings, you can approach from virtually any direction. However, the guide below will give the recommended approaches to make it as easy as possible.
Map of Poes
Poe #1 - Right at the entrance to the ruined bridge leading to what remains of Hyrule Town is a sign. Passing by it will cause the Poe to appear.
Poe #2 - At the entrance to Lon Lon Ranch is a tree. Pass by it (in particular between it and the wall) to make the Poe appear.
Poe #3 - In the northwest (top left) corner of Hyrule Field are tons of little black bushes next to a stream. One of the triggering locations for the Poe is atop one of them. Find it, then run through it when you're ready.
Poe #4 - Between Lon Lon Ranch and the entrance to the Gerudo Valley area is a tree all by itself. I find it easiest to face towards Hyrule Castle and run along the right side of the tree.
Poe #5 - Near the entrance to Gerudo Valley, where the road forks right before the ground color changes, stand on the ground between the road and the wall (right side). The easiest way to catch this one is to face right and try to get him to pass through the hole there. By far, the most frustrating one.
Poe #6 - In the south part of Hyrule Field, between Lake Hylia and Kokiri Forest are tons of trees. Find the patch of bushes and run through them to make this Poe appear.
Poe #7 - In the same spot, there's a regular brown boulder waiting all by its lonesome. The triggering spot to make the Poe appear is the tree directly south of it. I suggest facing towards Lon Lon Ranch and running north, along the tree's right side.
Poe #8 - Along the road between Kokiri Forest and Lon Lon Ranch is a silver boulder. Stand at the top, inside of the “Y” shape of the road next to the boulder to make it appear.
Poe #9 - Wait in the corner of the “V” shaped wall to the west of Lon Lon Ranch. You can either stand on top of it and wait or run along side it below.
Poe #10 - Near the entrance to Kakariko Village, there's an overhang above the stream. It's just this general area that makes it appear, so you can either wait on top or run through the pillar supporting it alongside the stream. I find it easier up top.