When these waves reach our ears, they cause the tiny bones in them to vibrate a certain way. The attached nerves send signals to the brain which interprets what the sound is.

Sound is a mechanical wave.

To understand the concept of mechanical wave lets take an example-

when we throw a stone in still water of a pond, we see that a disturbance is produced at a place where the stone strikes the water.This disturbance advances outwards in the same form and reaches the edges of the pond.

Thus, a mechanical wave is a disturbance produced in a material medium and advancing with a definite speed in the medium without changing its form. thus, the mechanical wave transmits energy and momentum throgh the limited motion of the particles of the material medium while the medium remains unshifted.

Coming back to sound waves, u cannot see them travelling but you can feel them.if the medium particles oscillate perpendicular to the wave , that mechanical wave is called a transverse wave . sound travels as a transverse wave in solids and surfaces of liquids.

if the medium particles oscillate parallel to the wave it is called a longitudinal wave. sound travels as a longitudinal wave in gases and inside liquids.

now answering ur question, let us suppose a table. if i hit the table the mechanical energy of my hand is transferred to the molecules of the table in the form of heat and sound.sound waves produced travel as transverse waves in the table (and the table molecules oscillate one by one along the direction of propogation of wave) and as longitudinal wave in air( such that air molecules oscillate one by one parallel to the wave ). now there are two friends A and B. A has his held in air. A hears sound as the sound waves reach the ear drum through the air molecules . similarly, B hears sound as the sound waves reach the ear drum of B via the table.

the air molecule that are in contact with the ear drum oscillate

When these waves reach our ears, they cause the tiny bones in them to vibrate a certain way. The attached nerves send signals to the brain which interprets what the sound is.

Good luck:)