The church year is a sort of calendar that focuses on certain days, seasons, and commemorations during the year. The structure draws us to the act of salvation that has been marvelously accomplished through the work of Jesus Christ.
In general, the church year is divided into three main 'Times': The Time of Christmas; The Time of Easter; The Time of the Church. Within each main 'Time' are the seasons (e.g. Advent Season, Lenten Season, etc.). Within each season are individual Sundays or particular commemorations (e.g. Second Sunday in Advent, First Sunday in Lent, Good Friday, etc.).
Certain colors are also associated with the seasons and even notable days of the church year. These colors (e.g. red for Pentecost, white for Christmas, etc.) are displayed on the altar, at the pulpit, and on the stole that the pastor wears during those specific times.
The below list gives a very general sense of where we are in the church year:
The Time of Christmas = end of November - end of February
The Time of Easter = end of February - end of May
The Time of the Church = end of May - end of November