I assume you are referring to the ordinary form of the Roman Rite, which is the Rite that most Catholics are familiar with. There are other Rites within the church, both Eastern and Western, but I'll omit those.
The Church year in the Roman Rite starts with Advent, beginning of December or so.
The season of Christmas begins on December 25th (or the vigil of Christmas the evening before), which lasts until the Baptism of the Lord in mid-January.
Then Ordinary Time starts, which is interrupted by Lent, which starts on Ash Wednesday (roughly six weeks before Easter) and ends on Holy Thursday. Holy Thursday begins the season of the Triduum (meaning three days), which lasts through Holy Saturday and ends at the Vigil of Easter.
Then the Easter Season begins and lasts until Pentecost (50 days). Ordinary Time picks up again until Advent of the succeeding year begins.
A diagram is available here:
- Does that answer your question?