In English/American checkers, an uncrowned piece is called a man. With no capture available, it moves one square diagonally forward into an empty dark square. Forward means toward that piece's far edge, not always toward the top of every picture.
Worked example
A red man on square 10 can step to 14 or 15 if those squares are empty and no red piece can jump. It cannot step sideways to 9, backward to 6 or two empty squares at once. Follow a corner-to-corner diagonal.
Your Small Position
Red has one man on square 9. White has one man on square 24. All other squares are empty. It is red's turn. Red moves toward the top of this picture. No capture is available. Study the two empty dark squares diagonally ahead of square 9.