Promotion is lesson 2 of 3 in Castling, promotion and en passant, a basics course suited to players rated around 350 (complete beginners). A pawn that reaches the last rank is promoted. It has 3 interactive exercises: 3 find-the-move puzzles. You play every move on a board and get feedback straight away. The lesson is free.
What this lesson explains
When a pawn reaches the far side of the board, it must become a queen, rook, bishop or knight of the same colour. Almost always you pick a queen. You can have two queens or more!
What you practise
Promote your pawn to a queen.
The pawn cannot go straight ahead: the knight blocks it. But it can promote by capturing!