Answer:
Here we consider the propagation of a transverse wave on a string.
In a transverse wave, the vibrations of the beads in the string occur in a direction perpendicular to the direction of propagation of the wave.
This means that, if the string is horizontal, the wave in the string propagates from left to right (for example), while the beads in the string move up and down, in the vertical direction (so, perpendicular to the direction of propagation).
The propagation of the wave occurs because when one bead starts moving up, then it "pulls" the adjacent bead also upward (because the two beads are connected). The second bead also pulls its adjacent bead upward, and so on. As a result, each bead does not move horizontally, but only vertically; so there is no transfer of matter in the wave. However, the vibration is transmitted horizontally along the string, therefore we say that the energy is transmitted in the horizontal direction (the direction of propagation of the wave).