It's kinda like pressing pigments, so if you look for one of those tutorials?
Here's my summary:
Put all the e/s in a pan, and keep adding alcohol until it reaches about a soupy consistency with all the shadow. If you still have most of the eyeshadow, than the mixture will overflow from the pan, and you will probably lose some product. If you use too much alcohol, you will lose a little product, but no harm is done b/c it will just take longer to evaporate. When you have your mixture wait for it to be mostly dry, and then take some fabric and a quarter (old fabric, b/c the pigment will dye it) and press down. You can repress it many times after that without any difference as well. Then just wait for it to completely dry (it will no longer smell like alcohol) and you're done =)