The Faithful are to approach the altar rail, kneel and kiss the hand of the celebrant when receiving a candle from him.
After receiving the candles, the Faithful do not retreat to the pews, but stay in the area in front of the first pew. Each candle will be lit here by the ushers, and then all will join in the procession behind the celebrant. The candles are extinguished after the procession.
The ushers will re-light the candles just before the singing of the Gospel. After the Gospel, the candles are extinguished.
Again, the ushers will re-light the candles during the Offertory. These remain lighted all through the Canon of the Mass and during the reception of Holy Communion. After the Faithful have received Holy Communion, when the gate of the Communion Rail is re-opened, the candles may be extinguished.
The above are directives for those attending at St. Stephen's. Things may be different at other parishes.