Go to Rito Village to ask the elder about the Divine Beast Vah Medoh.
Go to Rito Village
Before you go to Rito Village, you might want to activate Central Tower.
Float down off of the north wall of the Great Plateau, then go west along the dirt road. If you have not yet tamed and boarded a horse at a stable, tame a wild horse in the hills north of the Great Plateau. Then go west on the path that goes along the north wall of the Great Plateau. At the fork in the road, go northwest to find Outskirt Stable. Get a horse there if you have boarded one before, or register your horse if you just tamed one. The shrine near the stable is Rota Ooh Shrine.
Then go north on the road near the stable. You will cross Manhala Bridge, then there will be a fork in the path. Go right (North) at the fork. Eventually you will pass through Sanidin Park Ruins, and shortly after that you cross Jeddo Bridge. Then when the path splits, you can optionally go to the right to activate Ridgeland Tower. If you activate the tower, go south to return to the road.
Go west at the fork in the road that is north of Jeddo Bridge. After a while, you will reach the Tabantha Bridge Stable. The Shae Loya Shrine is on the hill south of the stable.
Then go west across Tabantha Great Bridge. You will see a Guardian Skywatcher on the path ahead. To avoid it, if you are on horseback you can carefully avoid their spotlights, or if you are not on horseback you can climb up the hill just after the bridge. Go northwest on the hill. There is a Great Fairy Fountain on the northwest end of the hill, so you might want to visit it before you continue.
From the northwest end of this hill, you can see Tabantha Tower. Climb and activate it.
From the top of the tower, you can see Rito Village to the north. It has a tall rock spire coming up from the middle of it. The road that is east of Tabantha Tower will lead you to the village. You will pass by the Rito Stable as you approach the village.
When you get close to the center of the village, there will be a cut scene showing you the Divine Beast.
Go to the village and make your way up the walkway that spirals up the rock spire. Near the top, you find the Akh Va'quot Shrine. After visiting the shrine, keep going up the spiralling walkway until you reach the house at the top. The elder is there. Talk to him. When he asks, tell him that you have a Sheikah Slate, then listen to his request.
After he tells you to find Teba, go into the house next to the elder's house and talk to the Rito there. She tells you to go to the Flight Range to find Teba. She says that you can get to the Flight Range by floating from Revali's Landing, which is next to her house. You will recall a memory of Revali.
You will need protection from the cold. You can purchase the Snowquill armor set here in Rito Village.
You can float to the Flight Range from Revali's Landing as mentioned above. Then visit the Sha Warvo Shrine.
Afterward, go north to the Flight Range. Go into the building and take the bow and arrows that are sitting inside. Teba is sitting on the landing overlooking the windy area. Go toward him and there will be a cut scene. Talk to him and offer to help.
He asks you to shoot five targets in three minutes. After the countdown, fall off of the landing and use the Paraglider. Then draw your bow. Time will slow down, giving you more time to aim as you fall. Your stamina will deplete while you aim, so don't take too long. Your stamina gets refilled when you use your Paraglider again. Float around shooting targets until Teba calls you back.
Teba says to take the bow from the treasure chest, so take it, then talk to Teba if you are ready to go to the Divine Beast. He will give you 20 Bomb Arrows and tell you to have protection from the cold.
A Duplex Bow is helpful here because it can do double damage, allowing you to kill each cannon with one shot instead of two.
Enter the Divine Beast
If you are ready, Teba will fly you up to the Divine Beast. You need to shoot the cannons at the edges of Medoh's force field. If you need to stop, just float straight up with the Paraglider.
Get as close as possible to each cannon before firing to help ensure that you don't miss the target.
Medoh will try to shoot at you if Teba is not close enough to draw its fire, so be sure to let go of the Paraglider when a cannon shoots. You will fall quickly enough to avoid the laser blast.
After you have killed all four cannons, you can enter the Divine Beast.