Consider a tube filled with air. The molecules are evenly distributed in equilibrium.
Blowing into the end of the tube will push the air molecules away, causing a rarefaction, which in turn causes a compression on the other side.
The high pressure of the compression then pushes outward, causing compressions on either side of it, and creating a rarefaction where the compression was.
The new compressions push outward, causing new compressions and creating new rarefactions. The wave moves through the tube and system continues to oscillate at a steady frequency.
Graphing the location of any molecule across time will result in a standing wave.