"In the Sacrament of Holy Orders, or Ordination, the priest being ordained vows to lead other Catholics by bringing them the sacraments (especially the Eucharist), by proclaiming the Gospel, and by providing other means to holiness."
Holy Orders is the sacrament through which the mission entrusted by Christ to his apostles continues to be exercised in The Church until the end of time: thus it is the sacrament of apostolic ministry. It includes three degrees: espiscopate, presbyterate, and diaconate.
Cathechism of the Catholic Church Page 382
Holy Orders is administered by a Bishop. Its celebration calls for as many of the faithful as possible to take part. It should take place preferably on Sunday, in the cathedral, with solemnity appropriate to the occasion.
Cathechism of the Catholic Church Page 393