At the start, there’s an option: to walk next to the priest or in front of him. What does your parish choose, and why?
172. 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.
One colleague, in handling things like this, suggests symbols do not bow to other symbols:
173. 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 a praiseworthy practice for him to 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 being used, he assists the Priest in putting some into the thurible and in incensing the cross and the altar.
174. Once the altar has been incensed, the Deacon goes to the chair together with the Priest and there stands at the Priest’s side and assists him as necessary.
The inclusion of the deacon in the penitential act has always been a puzzle to me. I know it’s widely done, but the reconciliation aspect of the Church’s sacramental life has long been reserved to presbyters and bishops. And the absolution formula is reserved to the presider alone, of course. Still, the splitting up of such a brief and important rite is curious. It requires some care and attention to do well.