The drum is not used in all shamanic traditions. In South America, for example, it is the icaros – songs – that punctuate the rituals and guide souls.
In Siberia, we systematically find the use of the drum, regardless of the tribe we visit. Traditionally, you don't become a shaman by choice, it is the Spirits who designate the man or woman who will fulfill this function within the community and it is this same community which will craft the shaman drum, drum to be given to him/her during the ceremony of officialisation of his/her function.
You know that drums help people to journey. It is the mount that the shaman rides to journey the invisible worlds to meet the Spirits. In traditional societies, the drum is always a healing drum, because if the sound has an undeniable effect on the environment, everything that composes the instrument has also its importance (the wood of the frame, the animal that gave its skin, the symbols that are drawn or painted, the bells, the pieces of cloth and especially, the pieces of metal).
When trance is induced during a ritual, all present and sufficiently sensitive people observe that the roles are balanced between the shaman and his/her drum: the ego of the shaman fades while the soul of the drum is expressed, the shaman becomes the instrument, the drum becomes the officiant, harmony and collaboration reigns between these two entities that become one. The drumstick guides the human arm towards the skin to emit such a sound rather than another, to touch such a symbol and not the one next to it. Nothing is the result of chance, but nothing is either premeditated.
Because he/she receives the teaching of his/her drum, only the shaman is able to decode the messages and a unique link connects them. It is for this reason that when the shaman dies, his/her drum is destroyed. Only the pieces of metal containing the Spirit of the instrument loaded itself, by practical means, by the Spirits of the Ancestors are preserved, and because they are so loaded, these pieces of metal will adorn the drum of the next shaman, which the Spirits will call when they recognize him/her.