What happens when I get a pawn to the other side?

When a pawn reaches the opposite side of the board, it promotes. This means that the owner of the pawn can replace it with a queen, a rook, a knight, or a bishop of his own color, and put that piece instead of the pawn on the board on the square of the pawn.

Can a pawn kill a king?

it can only be checkmated. a checkmate is a position in which the king is under attack and at the same time the king cannot defend against the attack (the attacking piece cannot be taken, the line of attack cannot be blocked, the king has nowhere to move that wouldn't also be under attack).

Can a pawn attack on the first move?

Pawns can not on the very first move of a game capture anything since there are no pieces to be captured on the squares to which a capturing pawn from its original square would move when capturing.

Can a pawn move sideways?

The pawn piece has the fewest options of any chess piece on the board in where it can move and it can only move forward until it reaches the other side of the board. Pawns can move directly forward two squares on their first move only. Pawns can move diagonally forward when capturing an opponent's chess piece.