There are four points within a month that mark the days that the Rite of Sacrifice should take place, following four phases of the moon. As the Rite of Sacrifice isn't a Sacrament, like the Communion Rite, it does not have to be performed by a priestess, so any Filianist may perform the Rite of Sacrifice.
One can certainly also perform the Rite of Sacrifice (abbreviated from here on out as the Rite) at any time, but these four days are the traditional ones. The Rite is also performed on major Festival days. When performing the Rite on the Natural Rite days within a month, there will be a note for Lection, which is the traditional reading that is read from Scriptures.
The altar will have some additional items from the very basics, and traditionally the altar cloth is violet unless one is matching the seasonally observed colors. More on that will be found at the Wheel of the Year page.
The altar should contain a blessed statue, chalice, brazier, incense, the sacrifice, the amphora, and optionally flowers or candles. The altar should face west, so that a celebrant may face East while performing the Rite.
Please use caution when working with any type of fire element, and take care that you have steps in place to contain any risks that come of using incense, candles, or any type of flame.