Basically, the number 4 represents the 4 directions, the 4 elements, the 4 seasons, and the 4 medicines that are used in ceremonies.

Before a sacred fire is lit, people are asked to become fire keepers for the duration of the fire, which means making a commitment to take part in taking care of the ceremonial fire. It means that a person accepts the responsibility to be a helper in maintaining the fire for 24 hours per day, for 4 days until whichever ceremony is complete. Usually, people attend to the fire in shifts and may stay as long as 8 hours or more during this time. Food and beverages are bought to the keepers from other volunteers.
The fire is not allowed to go out and is continually fed with the standing nation ( wood ), who have given their lives to become a part of the ceremony. When the wood is gathered, Tobacco ( semma) is offered to the spirits of the wood, asking permission and giving thanks for being part of the fire.

When the fire is prepared, I place cedar boughs on Mother Earth on which the wood will be positioned along with birch bark, which will lit in order to ignite the wood. Before, lighting the fire, offering of tobacco, cedar, sweet grass and sage will be offered and placed on the wood. We do this with good thoughts and prayers to request healing for ourselves and those who are not able to participate in this ceremony.
The fire is then lit, generally in the eastern direction, thereby signifying the dawn of new life. From that point on until the ending of the fire, the grandfather (fire) is treated with respect as if it were your own relative. Garbage, cigarette butts are not thrown into the fire and we do not spit into the fire either. As I stated, we treat the fire like our own grandfather and respect it as so.
During the duration of the fire, people may come and visit to make their offering and prayer for themselves and others. Many times, a talking circle is held around the fire, where people share their stories and healing prayers. Pipe ceremonies, drumming are also a part of the ceremony.
A closing ceremony takes place when the 4 days are complete, the fire is allowed to burn itself out.

In closing I would like to add that many spirits visit the fire during this time and people receive many good teachings while just being around the fire. As you know, a gift that we receive while being with fire, is a good feeling of peace and harmony, which in turn serves in healing our inner selves,

Ahow, Meegwetch and may the Creator take care of you and your loved ones.

In the Spirit of Healing and families.