level editing question. WHAT!? again?

Well you know that level in sonic the hedgehog 06/sonic next gen, that where sonic run all time and fast. i wonder how to do something like that.
i know that much (maybe) i must use some linedef what is in ''wind/current''
folder. but what i use on them and how. how i choose direction where character go to run?

Tagged sector must have Sector Type 512.

In a closed polygon of linedefs, the linedefs that have the notches facing inwards go clockwise around the polygon. Linedefs whose notches face outwards go counterclockwise around the polygon.

Also, look here.