One significant aspect of shamanism is journeying. This could either be questing within or using the Tree of Life as a guide. Journeying is done by imagining or visioning. You will enter what is often called an "altered state of consciousness" or an "ecstatic state." Basically it is a deep meditative trance in which you journey, most often with the help of a spirit guide, within yourself or using the Tree of Life as a map. Journeying allows you to communicate with your spirit self and with the web of power.
Most shamans use drumming to help them into and out of a trance state. You do not have to use drumming, and rhythmic sound will work, for example ocean waves. You may use tapes, but it is best if there is some control over the rhythm to adjust it as the need arises, so it is preferable have "live" music. You may either drum yourself or have someone drum for you (which gives you the added benefit of having someone to watch your body as you travel). You can journey without the sound, but it really does help you get into the mood and go into a trance easier. It also helps call you back from your journey. I would suggest that you do not try to travel without it until you are very comfortable with the process. Besides how hard is it to find something to tap on? You do not have to have a fancy drum, an empty tissue box will do in a pinch.
The length of a journey depends on the person and on what they are trying to do. Try and make sure that there will be no interruptions. If you find outside thoughts intruding just accept them and move on. The same holds true if you try to judge what you see. Just accept that your mind is trying to judge then move on.
When you travel remember to be respectful, calm and patient. You won't get very far if you aren't, in fact you will probably get some rather amusing lessons on it. Normally the answers you get will be simple and direct, they can also come in puzzle or dreamlike form. If so there is often more to it than there seems. Do not try to think it to death just let it rest and you will understand when it is time. Accept what you are shown or given (gifts from the spirit world should be treasured) even if what you see makes no sense to you at the time. Trust that it will eventually when the time is right. You should have no expectations or preconceived notions of what you will find in the spirit world, if you do it can skew what you find there.
If you try to journey and nothing happens don't panic and, no, you probably did nothing wrong. Don't stress about it. You might not be ready or it might not be the right time. Just wait and try again later. Timing matters and remember that practice makes perfect.