Quick start guide

Get yourself some dye.
Fiber-reactive dyes that react at room temperature.
Procion brand of dyes are safe, and affordable.

Get yourself some fabric.
Any type of clothes made from natural fibers.
Plain old cotton shirts are the best for beginners.

Get yourself some washing soda.
It activates the dye and make it react with the fabric.
You can get it easily in most supermarkets.