natalia88,here are a few links to help you get started. Please don't hesitate to ask any questions here. It sounds more complicated than it is. After a few times I'm sure you'll agree that giving yourself an enema is really easy, and not so bad at all.
It's just that the first time if you are doing it on your own it can be somewhat awkward. Just make sure the water is not too hot or too cold, and that the bag isn't hanging too high. The water should be 103 degrees F or 39.5 C, and the last link shows the proper height of the bag.