A “Hukam” (also called “Hukamnama”) is an order, proclamation, command, or instruction from the Guru. To receive a Hukam, Sikhs open the Sri Guru Granhth Sahib, the living Guru of the Sikhs, at random, with great reverence, following the Ardas (prayer), and let the Guru fall open where it may.
Then, the verse is read on the page that opens. Sikhs receive it as the order to follow for the day, or for the particular purpose for which they prayed in the Ardas. Because the Sri Guru Granth Sahib is the Sikhs’ living Guru, whatever is read is accepted as a direct message from God and Guru to take to heart and act upon.
During Gurdwara, the Hukam is read after reciting Ardas, the concluding prayer of the service, and before the serving of Prasad (special food blessed by the Guru), which ends the service. To take the Hukam, the Guru is opened at random. The Hukam is read from the beginning of the verse, or pauree, on whichever page the Guru is opened, to the end of that verse (pauree). All preceding aspects of the Gurdwara serve to prepare the listener so the words of the Guru may be inscribed in their hearts.
Outside of a Gurdwara service, any individual or group may take a Hukam at any time to seek the grace and guidance of the Guru. When doing so, one is expected to approach the Guru with all purity and devotion. One must always have the head covered and wash their hands before taking the Hukam. Ardas or a prayer is always said before taking a Hukam. The Guru should always be opened at random to demonstrate that one is giving themselves entirely over to God and Guru. The Sikh accepts the message they receive in the Hukam into their heart, and tries their utmost to live by it.
~Resource: Living Reality (1994) by Bibiji Inderjit Kaur Khalsa.