The red stars are the flagposts, signs and crates are indicated by black dots.

The Wasteland HESS is a notably difficult trick and requires a lot of practice. It is typically carried through the whole Wasteland ("full Wasteland HESS") or dropped at the building with the guiding Poe ("half Wasteland HESS"). The video is an old but still useful tutorial by zfg.
It's also possible to cross the river of sand by backwalking.
This video demonstrates the hoverslide with a superslide, but it can also be done with a HESS.