Hyrule has a lot of mysteries and challenges to uncover in The Legend of Zelda: Tears of the Kingdom, and you can discover a lot of those just by exploring them. Many of them aren't even in your path should you follow any of the main or side quests, so always be willing to go off the path and find something you would never have before.
If you do, you might come across a quest like The High Spring And The Light Rings, which you can find in the eastern area of Hyrule, Lanayru. Should you explore this area, you will come across this quest that have you shredding it up on the mountain and doing so in style.
Start The High Spring And The Light Rings
You can find this quest by going to Mount Lanayru, specifically going towards Mount Lanayru Skyview Tower. If you go down directly southeast from the tower, you will find the Spring of Wisdom. This area has a large Goddess Statue that you can exchange any Blessings of Light you have, but also has an NPC nearby you need to talk to.
Near the entrance to the Spring of Wisdom is an NPC named Nazbi. This incredibly overeager - and overconfident - treasure hunter will explain that there is some rumored treasure on the mountain involving rings of light and more. That's all he has to offer you, and the quest starts.
Complete The High Spring And The Light Rings
While the quest is given to you on the ground, you will actually have to continue it in the sky, specifically on a sky island above you. Head back to the Mount Lanayru Skyview Tower and use it to launch yourself up into the air. When you are able to glide, look around for a sky island in the shape of an ice cream cone. Head to this island and land on it.
There, you will find some kind of Zonai machine you can interact with, along with a few shields lining the walls on your sides, specifically shields you can use to Shield Surf. This should give you a clear indication of what you are about to do.
Go up and interact with the Zonai machine to begin the challenge, which involves shield surfing not only off this sky island but also landing on the mountain and continuing to surf down the slope through green rings, all within a set amount of time.
When you start the challenge, you will see the first green ring off the island after a slope you have to start your surfing from. In order to Shield Surf, all you have to do is press ZL to bring your shield up, use X to jump, and then press A in the air to hop on your shield and begin surfing.
You will go off the sky island and through the first ring, and light will shoot off toward the ground to show you where the next one will be. It's pretty much directly beneath you, so you don't have to worry about gliding too far.
Just be careful about landing: be sure to use your glider to save yourself from a very brutal death. Dismounting your glider will put you back on your shield without losing any time.
From here, it's a standard run down the slope, weaving around corners and going through the green rings until you reach the end. It's all very easy to get through and shouldn't give you much trouble at all.
Once you have finished the course, you will reveal the Zakusu Shrine in front of you, and the quest will come to an end.