Carrying the Book of the Gospels slightly elevated, the deacon precedes the priest as he approaches the altar or else walks at the priest’s side.
When he reaches the altar, if he is carrying the Book of the Gospels, he omits the sign of reverence and goes up to the altar. It is particularly appropriate that he should place the Book of the Gospels on the altar, after which, together with the priest, he venerates the altar with a kiss. If, however, he is not carrying the Book of the Gospels, he makes a profound bow to the altar with the priest in the customary way and with him venerates the altar with a kiss. Lastly, if incense is used, he assists the priest in putting some into the thurible and in incensing the cross and the altar.
After the incensation of the altar, he goes to the chair together with the priest, takes his place there at the side of the priest and assists him as necessary.