I found this on the wikia, credit t those who helped put it together.
Video credit to CtU
Glowing Symbol Locations
The Beginning
1. The first symbol the player comes across-this creates their scarf.
2. In the hub area (right before the end of the level), check the right side to find a symbol on top of a pillar. This symbol can also be acessed later from the Chapter Select area when the player completes the game.
3. On the rocky tower in the hub area, this symbol is hidden on the left side. Follow a trail of rocks to find it, or simply fly up if you have the energy.
The Bridge
4. Due west from bridge start point. Near rocks.
5. West side of the bridge end, hidden in a rocky alcove.
6. Above the sand waterfall-an ancient glyph is underneath.
The Desert
7. Go north over two dunes, then go north-west. On a tower.
8. South-east corner of The Desert.
9. North-east section of The Desert.
10. Top of the tower at the end of the level. Around to the left.
The Descent
11. On the first downhill, directly behind the first tower.
12. Right as you drop into the first space with the ribbons, you will see an alcove above the waterfall. Either angle yourself while falling or fly up to land on it and find the second glyph.
13. Second downhill. Behind second tower, jump across rocky path.
The Tunnels
14. Inside a pipe jutting upward.
15. Inside criss-crossing pipes with the kelp-like cloth.
16. In the room with the jellyfish, on top of the highest one.
17. Back left side of the second room patrolled by serpents.
The Temple
18. Left side of the central pillar after activating first panel.
19. Right side of the room, behind a grate, after second panel.
20. Behind the cloth banners in room where the cloth dragon emerges. After third.
21. Inside the central pillar, a few levels from the top.