According to the informations contained in the book of the French authorCyrille Javary, entitled "Le Discours de la tortue", the first consultations were done during the sacrifices by examining the bones of the slaughtered animals. Then the sacrificers used turtle shells, until the appearance of the yarrow sticks, then the money coins. Today, we often use the computer.
The choice of a method is not neutral because the probabilities to obtain a specific hexagram are different. Those who defend the principle according to which the consultation of the I Ching is a subconscious activity will generally prefer using yarrow stick, will distrust the coins and reject the consultations by the mean of a computer. I was saying before that what we think about the I Ching has an influence on the range of our questions, it is also true with regards to the choice of the consultation method.
This method is the longest and the most complex, a consultation will typically last about twenty minutes. Here is a video tutorial for those who want to consult with the Yarrow sticks:
Remember that if you obtain a group of 8 or 9 sticks, the value associated will be 2 and if you obtain a group of 4 or 5 sticks the value will be 3. By additioning the 2s and the 3s you will obtain 6, 7, 8 or 9 that will correspond to the consultation with coins. You can enter those numbers and use the "Manual" button on this site to obtain your hexagram directly.
This method is much quicker than the yarrow sticks and is often criticised by the purists. The main reason being that you won't have the same probability to obtain a changing line if you consult with the coins compared to the yarrow sticks. Here is another video showing you how to consult with coins.
A head has for value 3 and a tail 2. So, when you throw the coins and obtain three tails it is a 6 (2+2+2), an old Yin line that will transform into a Yang line. When you obtain 3 heads you get 9 (3+3+3) which is an old Yang line that will transform into a Yin. Two tails and a tails result in a 7 (2+2+3) which is a young Yang line that won't transform and finally two heads and a tail give a 8 (3+3+2), a young Yin line that won't change either.
Once the six lines obtained, you can see the comments on this site with the following internet address: http://taoscopy.com/en/consultation/??????, where the 6 question marks have to be replaces by digits from 6 to 9. Alternatively you can type the six digits and press the "Manual" button.
If you don't have any Chinese coin, you can use modern coins.
For example, if you have obtained like the lady on the video 678797 you can read your comments at the address http://taoscopy.com/en/consultation/678797/
As we have seen it, for those who consider the I Ching as a method of interaction with our subconscious, the consultation by the means of a computer can seem futile. Those who think that it is about synchronicity or an oracle may have a different advice.
On this site you can consult the I Ching by clicking on the 'Oracle' button. The statistics are the same than the yarrow stalks method.
I won't detail the other methods, but I can cite the usage of two coins which has the same statistical rate than the yarrow stalks. Another method relies on marbles. If you don't have yarrow stalks you can use cards. Some people also use dices, four, six or eight coins. You will find more details in this article.