Here's how it works:

1. Wave Erosion: Waves relentlessly pound against the cliff face, eroding it through processes like abrasion (rock fragments carried by waves grinding against the cliff) and hydraulic action (the force of water compressing air in cracks, breaking them apart).

2. Formation of a Notch: As erosion progresses, a notch is formed at the base of the cliff, where the waves are most concentrated.

3. Platform Development: The notch continues to grow and eventually forms a platform, extending outward from the cliff. This platform is carved out by the continuous erosion.

4. Cliff Retreat: As the platform widens, the cliff face retreats inland, leaving behind the wave-cut platform.

So, the process starts with a cliff, and the platform is a product of wave erosion and cliff retreat.