When two waves overlap, their total displacement is the sum of the individual displacements of the individual waves. This is the
principle of superposition of waves which is applied to explain the formation of stationary waves and interference patterns. Possible application of interference patterns are holograms in physics of optics and coastal erosion in geography.
Let's watch a video to review the concepts of superposition due to two sources.

YouTube Video:Physics Lab Demo 14 Ripple Tank


Initial understanding of superposition