Unlike the other pieces, the pawns can move in only one direction. Forward. Ever forward. Reach the final rank and the lowly pawn, the foot-soldier of chess, can transform itself into any other piece, though almost always into a queen. And yes, you are allowed to have more than one queen on the board, though it is very rare to see more than two. If you are lucky enough to have more than one queen, either borrow a queen from another set, or else take one of your captured rooks and turn it upside down. Chess players understand that an upside-down rook represents a second queen.
As the pawns move forward, they open up diagonals for the bishops, protect other pieces, and often lead the way for attacks. They can pry open an opponents' kingside, but they can also spell doom when they become weak and are easily subject to capture.
In the following diagram, white's pawns are considered very strong despite the fact that they have not yet moved. We say that there are no pawn weaknesses in white's camp. By contrast, all of black's pawns are isolated and weak. Without addition captures, it is not possible for any of the black pawns to protect to protect the others. As you play chess, you should generally try to keep your pawns coordinated. Think of them as the foundation of your house. Every crack and every hole can eventually lead to disastrous consequences for the whole house.