You just mark the fabric with permanent sharpie markers. Then, spray with the alcohol or use an eye dropper or paint brush to apply the alcohol to the ink. It will slowly start to expand and soften the area of the sharpie marks. And, swirls, dots, streaks all leave different "dye marks". Pinterest has some great tutorials. And, more alcohol makes the ink run more, less alcohol does the oppositel. I would suggest playing with small test pieces first. (Which I've done.) I have not used or tried the knock off brands. I've heard to stick with the sharpies. I always "dye" my fabrics first. Or at least I did on most of the examples I posted. The little girl one, I used the alcohol after I colored and embroidered. Hence, some issues with ink runnage.
Here's some interesting tutorials. These two were particular favorites.
https://www.creativeinchicago.com/20...ther-easy.html
https://www.creativeinchicago.com/20...uper-easy.html