I've only tea dyed a few of times, but I love the results. I just boiled water and put it in a big bowl with a few tea bags (many if you want the dye to be fairly dark). Take the tea bags out when the "tea" is the right colour. Let it cool, then drop in the fabric, make sure all the fabric gets wet, I agitated it a bit with my hands which is why I let the tea cool. Pull it out, check if the colour is what you are looking for. Rinse in cold water and dry normally.
The first time I did it, I tried it on some small samples of fabric first. Good luck and enjoy.