Satin is a woven fabric (so it is not elastic) with one shiny side, normally used as the right side. Because of that, if you put it face to face the parts get moved easy, because its a little slippery, so you better pin it carefully. Another thing you have to consider with satin is that it needs good overedging/trimming seams because it frays easily. Also if close to a more rough material it starts pilling meaning little knots of fabric on the fabric, so be careful.
You can buy it made of cotton but often it has some polyester fibers in it, because cotton is normally not very shiny. So best you ask what it is made of.
Since Satin looks elegant its mostly used for tops, skirts and dresses. But I also know it for pajamas and bed linen.
All the best for all your future projects