For the feast of St Bruno, here is a recording of part of the Office of Sunday Matins sung by the Carthusian monks at the Grande Chartreuse. The bells sound at midnight (1:35); the Office then begins with the introduction and Psalm 3, sung without an antiphon, followed by the Invitatory Adoremus Dominum * qui fecit nos, with the verses of Psalm 94, and the hymn Aeterne rerum conditor, one of the indisputably authentic hymns of St Ambrose. The first nocturn begins at 15:50, you can see that a piece of paper with the full text of the first antiphon has been pasted into the antiphonary, since traditionally, the antiphons would have been semidoubled. Psalms 20-25 are sung with one antiphon for each two Psalms, followed by the versicle, after which the Lord’s Prayer is said in silence. The readings are taken from 2 (4) Kings 19, which in the traditional order would put this on the 11th Sunday after Pentecost. The four responsories are taken from the traditional series read with the books of Kings according to the Carthusian Use; the fourth one, Domini est terra, is used by the Roman Rite in the season after Epiphany.
At the doxology, it is customary to stand and then bow, which accounts for the shuffling of feet and seats that one hears; the Carthusians also sing it very slowly. Of course, this video only includes the first of three nocturns; the twelfth and final responsory in the third nocturn is followed by the Te Deum, the Sunday Gospel, the brief hymn Te decet hymnus, and the prayer. According to the website of the Grande Chartreuse, Lauds is still done right after Matins. Laudabiliter vivunt!