Explain what happens at the saturation point when adding salt to water at room temperature.

See below  

Step-by-step explanation:

You won't see much happening. The solution is saturated, so the salt will fall to the bottom of the container and sit there. It will not dissolve.

However, at the atomic level, Na⁺ and Cl⁻ ions are being pulled from the surface of the crystals and going into solution as hydrated ions. At other places, Na⁺ and Cl⁻ ions are returning to the surface of the crystals.

The process is

NaCl(s) ⇌ Na⁺(aq) + Cl⁻(aq)

The rates of the forward and reverse processes are equal, so you see no net change.