You don't want to do any sanding after the stain is on or you will just remove it. Don't use steel wool on raw or stained wood. Small shards of the wool will embed in the surface and you will be depositing the oil that is present in the wool on your surface, which can cause adhesion problems for your top coat. Steel wool is often used after a top coat but not before. Do all your sanding before staining and don't do any more until you have a couple of coats of finish on, otherwise, you will rub through both top coat and stain.