The wrong step is - Step 2: Sediments are heated.
The beginning of the formation of the sedimentary rocks is in the weathering of the rocks. The weathering contributes to the breaking up of the rocks in smaller pieces, very often as sandy particles. After the erosion moves away the sediments, and they deposit at another place, which may be nearby or far away, depending on the conditions. With the deposition of the sediments, the material needed for the formation of the sedimentary rocks is on place, but the sediments need to be merged together, and that is happening with the processes of compaction and cementation. These two processes manage to stick together the small pieces of sediments, thus giving birth to the sedimentary rocks.
