Satin weave is most commonly created from very fine warp and weft yarns e.g. silk in combination with its specific weave structure to make a super soft and smooth draping fabric. It is constructed from long 'floating' warp or weft yarns passing over four or more of the perpendicular yarn.
This particular diagram shows a 4:1 weft-float satin weave; the weft yarn floats over four warp yarns, under one, and back over four. The point at which the weft is secured under a warp must be set into the weave at a diagonal, but this will always go unnoticed due to the long floating yarns which glide over the surface of the fabric.
Satin weave can be identified as having a contrasting front and back, the front will be smooth and lustrous, and the back will be rough and dull in comparison.