Here's the breakdown:

* Sedimentary rocks form in layers: Sediments accumulate over time, forming distinct layers called strata.

* Older layers on the bottom: As new sediments are deposited, they settle on top of existing layers. Therefore, the oldest layers will be found at the bottom of a sequence, and the youngest layers will be found at the top.

* Undisturbed sequence: This principle only holds true if the sedimentary rock sequence has not been disturbed by geological processes such as folding, faulting, or erosion.

The Principle of Superposition is a fundamental principle in geology and helps us understand the relative ages of rocks and the history of Earth.