Hot Fix Crystals can be used on most fabrics, cotton is best. You need a hot fix jewel applicator. It looks sort of like a soldering iron or a mini curling iron. Heat it up and put the jewel bottom side up on the tip of the tool and place where you want on the fabric. Follow directions for how long you need to apply it. Basically, there is glue on the bottom of the crystal and it melts, bonding it to the fabric.
I like swarovskis as they are much more sparkly. You can buy transferrable patterns to follow or you can use a pencil to make your own. I’ve drawn swirls and lines right on the fabric and used that for applying the crystals, I’ve also used stencils to make a template for painting and then embellished with crystals.