When I learned this technique we used a piece of tulle underneath and one on top to hold the silk down but I found it difficult to remove at the end so I just lay it on the craft mat instead.
Textile medium is the glue that is going to hold the silk together. You can use any brand, in the class I used Jo Sonjas but here I have used Folk Art brand. Dilute the medium with water (about 1/3 medium to 2/3 water) and use a foam brush to paint it on your silk. Make sure the medium goes all the way through your silk. Leave it to dry overnight and then you can peel it off your craft sheet.
You will end up with a piece of fabric that you can use any way you like.
Your silk paper will have some interesting textures.
I used silk paper on this index card.