You have already done the right thing by having her come into the bathroom with you, and explaining the process to her. You should also get a potty chair for her and let her practice sitting in it, even with her clothes on. Children are ready to train when they can sense ahead of time that they have to go, and give you some sign that they have to go (either in words or with their facial expressions). They also need to be able to sit for a length of time on the potty, and should be able to follow directions.
Another sign to look for is long intervals with a dry diaper or waking from a nap with a dry diaper. This tells you that her bladder is starting to be able to hold the urine for a while. If she has her bowel movements on a regular schedule, it also makes it a bit easier to start the process. Almost all parenting books have useful step by step descriptions of the rest of the process. Check your local library or bookstore to get the details.