It's difficult to know what source to use. The UK Reiki Association
seems to have omitted to say how they think it works.
The International Center for Reiki Training
also don't seem to say how it works, but says:
While Reiki is spiritual in nature, it is not a religion. It has no dogma, and there is nothing you must believe in order to learn and use Reiki. In fact, Reiki is not dependent on belief at all and will work whether you believe in it or not.
So far, so good!
Because Reiki comes from God, many people find that using Reiki puts them more in touch with the experience of their religion rather than having only an intellectual concept of it.
From Reiki for Christians
Reiki is a Japanese word that comes from two words - Rei and ki. In the Japanese language...the word Rei means universal spirit, Higher Power or God. The word ki refers to the life energy that flows through all living things. Therefore, Reiki means life energy that is guided by God. Some also feel this is just another way of saying Holy Spirit.
Reiki teachings state that there is a universal 'life force' energy, which can be accessed by practitioners to induce a healing effect. It is claimed by believers that anyone can gain access to this energy by means of an attunement process carried out by a Reiki Master.
The belief is that the energy will flow through the practitioner's hands whenever the hands are placed on, or held near a potential recipient, who can be clothed. Some teachings stress the importance of the practitioner's intention or presence in this process, while others claim that the energy is drawn by the recipient's injury to activate or enhance the natural healing processes. Going further, the belief is that the 'energy' is 'intelligent', making diagnosis unnecessary.
A second level of training, including another initiation, is said to equip the practitioner to perform Reiki treatments from a distance. This method, it is stated, involves the use of special symbols to form a temporary connection between the practitioner and the recipient, regardless of location, and then to send the Reiki energy. Techniques are also taught whereby Reiki can be sent to a specific point in time, either in the past or the future.
The energy involved in a Reiki treatment is said to be 'from the Universe,' rather than the personal energy of the practitioner, and is therefore inexhaustible. (Some teachings say that the energy enters the practitioner through the crown chakra at the top of the head, before being emitted from the hands.)As a consequence, Reiki practitioners are taught that they can treat themselves with Reiki.
Whilst this may be presented as an explanation, I can't see anything here that explains anything.
Can you point me to any source that explains reiki?