In the liturgical calendar, this is the first of six Sundays in the season of Lent.

The liturgical color is violet (or "purple").  

Images are veiled, except for the crucifix above the altar.

Enter to the chanted Introit with no Entrance Hymn.  The thurifer should move as soon as the bell is rung, even if the choir takes a moment to begin the chant.

The Litany is sung in procession at the solemn mass. (See DWM 1061).  If the procession begins in the nave it follows a figure-8 pattern through the nave, moving into the chancel at the words “all women in childbirth”.

If the procession begins at the outdoor shrine, it proceeds through the cloisters to the entrance to the church, and then straight through the nave as usual. The thurifer needs to halt for a moment a few pews into the main aisle at this point - to let the choir exit the procession and the sacred ministers catch up so there is not a large gap between servers and ministers.  

Following the Litany, mass continues with the Introit, Kyrie and Collect. The Collect for Purity and Summary of the Law are omitted.

The Proper of the mass is at DWM pg. 238.

The Gloria is omitted at all masses during Lent.

Alleluias are omitted.

The appointed Tract is used at the Gospel acclamation.  The altar party remains (standing) in the chancel stalls until about halfway through the tract.

When the Litany begins the liturgy, the Prayers of the People and the usual Penitential  Rite are omitted.  Mass moves from the Creed directly to the announcements and blessings. At other masses (ie not the solemn mass), these are said as usual)

The celebrant, rather than the deacon, says the Prayers of the People, using Form 1 (See DWM pg. 1048)

The Preface is the Preface of Lent (DWM pg. 588)

Trisagion may be sung during the Communion of the Faithful, before the Communion Antiphon.

Masses during Lent conclude with the special Prayer over the People (before the Blessing and Dismissal).  The Deacon introduces it with "Bow down before the Lord.", and the Priest says the particular prayer in place of the usual "The peace of God..." before continuing directly into the blessing "And the blessing of God almighty..."