There are probably tons of different tutorials on how to tie dye your clothes. This is how we did it.
First you soak your cotton shirt (or whatever article of clothing you would like to tie dye) in a water/baking soda solution for about 10 minutes. We used one box of soda with about 2 galons of water. This process helps the cotton fiber absorb the color better.
Then you pick were you want your spiral(s) to start. Twist, fold, etc. There are many patterns that can be found online.
Then secure your shirt with three rubber bands. These form the sections that you will dye.
We bought many different colors. Follow the mixing instructions and put the dye into squeeze bottles. We were a little more creative with water bottles and a nail hole in the lid (not recommended). The squeeze bottles worked much better.
Let your shirt rest in a plastic bag for 24 hours.
Rinse under cold water with ties still on. Switch to warm water while you until the folds. You want to keep rinsing your shirt until the water runs fairly clear. Put your shirt in the washing machine (hot water). We washed 3 times before wearing them. We washed them separately from our other clothes for a while. We didn't want to chance ruining our other clothes with the dye.