Answer:
Clastic sedimentary rocks are formed from the compaction and cementation of rock particles of various sizes which have been transported and deposited by the processes of erosion. Examples of clastic sedimentary rocks are shale, sandstone, and conglomerate.
Here's the process from start to finish, which can take millions of years:
It begins with the weathering and erosion of bodies of sedimentary, igneous, or metamorphic rocks; larger rock is broken up into smaller particles which are transported by moving water, ice, gravity or wind, and deposited at the bottom of a lake, a river delta, an ocean, or similar location where further movement is restricted or slowed down. The rock particles can range in size from boulders to clay particles less than .002 mm in diameter. If these rock particles are covered by additional particles, eventually the weight from above will start the process of lithification. Lithification is the compaction and cementation of particles which form rock. Compaction squeezes out the fluids and space that exists between the particles, and cementation results when the fluids that are squeezed out are replaced with minerals that were in the fluids. Once cementation occurs, the new sedimentary rock has been formed.