One of the rifts can be found in Gerudo Desert in southwestern Hyrule.

How to Go to Gerudo Desert

From Lueburry's house, go west to Suthorn Prairie. There is a treasure chest on top of a structure in the water. Stack several echoes on each other and put a trampoline on top to reach the chest. Open it to get 10 portions of rock salt.

In the pond north of there, you find some grass in a circular shape. Dive underwater to reach the tuft of grass in the middle of that circle, then press R to spin and cut the grass. You get a Might Crystal.

North of that, there is a cave. Go inside, then use a monster to defeat the Crawltula that comes down from above. Then stack echoes on top of each other to reach the first ledge, where there are 20 rupees. Then you can create a Strandtula and climb up the silk to reach the chest at the top, which contains 50 rupees.

Go west from there and talk to the person to start the quest The Blocked Road.

Go south from there, then west. Create a monster echo, such as an Ignizol, to defeat the bird that attacks. Try not to let the bird hit you, because you will drop some money if it hits you. When it's defeated, you can learn the Crow echo. You can use the Crow echo to fetch rupees for you as well as attack enemies.

Go north, and there are more Crows to deal with.

Use a trampoline to reach the ledge on the right, then go south. Create a bed echo, then a Decorative Shrub echo next to it, then make a trampoline on the bed. Jump on the trampoline to get on top of the shrub, then go up and pick up the rock to find a Might Crystal.

Go back down, and go west on the stone ledges. To the southwest, there is a tree with a treasure chest in it. You can go south of the chest, onto the ledge, and make a trampoline so you can jump up on the ledge to the south. Then you can face the chest and press X to bind to it, then walk to the side and press ZR to release it so it will fall to the ground. Open it to get 50 rupees.

To the north, there is a tree with a rock on it. You can jump up onto the ledge on the right and press X to bind to the rock. then jump while moving to the right to get the rock past the edge of the tree stump. A Might Crystal will appear. Create a bed, then a trampoline on the end of the bed, to jump up to get the Might Crystal.

Go south and west to find a waypoint to add to your map.

Then go west and there will be a cutscene. This starts the quest A Rift in the Gerudo Desert.