Unlike in the Novus Ordo, the celebrant in the Extraordinary Form prays most of the Our Father (or “Pater Noster”) by himself. The congregation and other ministers join only the last line: “sed libera nos a malo.”*
The Our Father follows the conclusion of the Canon, which is said silently. The priest announces the end of the preceding prayers by saying the conclusion aloud: “Per omnia saecula saecolorum.” The people respond “Amen,” and then stand for the Our Father. Following the Our Father, the people remain standing until the Agnus Dei, as in the Novus Ordo.
* This division of the Our Father was not unique to the Mass: it is frequently found in the traditional Breviary (at least following its revision by St. Pius X—I have not studied the Breviary as promulgated by St. Pius V in 1568, although those interested in this topic can read an exhaustive discussion in an extensive series of posts at the New Liturgical Movement; find the first part of the series here and the conclusion here). For instance, the ordinary for Prime specifies,”Pater noster then silently to V. Et ne nos inducas in tentationem. R. Sed libera nos a malo.”