Once a man enters the seminary, he enters into a deliberate time of priestly formation. The length of this period of time can vary, depending on when a man enters and what his background is. The general pattern of his formation begins with philosophy (whether in college seminary or in two years of pre-theology at a major seminary) followed by four years of theology (always at a major seminary).
The Program of Priestly Formation lays out four areas of growth: human formation, spiritual formation, intellectual formation, and pastoral formation. In addition to these, the man in formation also learns how to live in community. The overall goal of the program is to foster in a man a priestly maturity so that he can be a fully integrated individual who can serve Christ and his Church well.
Once a man enters theological studies, there are three "institutions" which a man receives as he gets closer and closer to ordination first as a deacon, and then as a priest. The man is received first as an official candidate (in the Rite of Admission to Candidacy), called and approved by the Church to begin proximate preparation for ordination. The man will later then be formally instituted as a lector, handed the Scriptures and commissioned to teach them and to live by them in word and deed. At some later point, the man will be instituted as an acolyte, in which he is given various duties to assist in liturgies as an instituted altar server, among other things.
After receiving these three institutions, and after completing the necessary theological studies, the seminary faculty and the vocations director may decide to recommend a man to the diocesan bishop to be ordained a deacon, and later a priest.