Actually there is no actual God in this blief even if Tengri means God. I think god is the cosmos here. Beacouse there is no description of an exact God but everything is a part of it, everything is sacred. If you wanna learn about Tengriism more, and you don't know Turkish, research...
When someone dies, there is three rituals.
1. Burn: a soul reaches to sky when it's burned.
2. Birds: This ritual is so old. You can see this in Çatalhöyük too. That's habitual to feed birds in religious rituals so God can join the feast. And it's also believed, a soul gets burried to sun or...