I read there supposed to be water under a lot of desert, and from the winds, stars and the Sun movement you can calculate where the fark to go.
You've got no clothes, so you can walk during the day.
How long is the longest expanse of sand before a tree, or shrub?
What reptiles, insects animals are there?
Or are you gona give up and try and make it quick?
Not really a question that can be answered with the info you gave.
I read there supposed to be water under a lot of desert,
Yep there is but depends on the desert and terrain.
and from the winds, stars and the Sun movement you can calculate where the fark to go.
I think sailors in the old days tried this and it seemed to work ok,still in use today.

You've got no clothes, so you can walk during the day
Bloody cold at night,naked in the desert to.
How long is the longest expanse of sand before a tree, or shrub?
How long is a piece of string?,again depends on what dessert you mean.
What reptiles, insects animals are there?
depends on what dessert you mean.
Or are you gona give up and try and make it quick?
Based on the question there is nothing around to try and make it quick,
Best i could think of was .....
beat myself over the head or choke myself with my ?????