Beginner question, mergeing layers

They may not need to be together. Layers seem to be merged up to the top selected layer however the document overall composite can be dramatically different then before the merge the merging order and position would be changed. I would think one would normally only want to merge adjacent layers.  Not Odd layers.

Also if there are targeted layers  (Ctrl+E) will show as merge Layers in the history palette.  If the is only the Active layer and (Ctrl+E) is used it will show as Merge down in the history palette and the current layer will be merged into the lower layer and the become the active layer with the name the lower layer had where merge layers merge all the lower targeted layers into the top most targeted layer and become the active layer with the upper layer's name. So Ctrl+E is both Merge Layers and Merge down depending conditions.

The ctrl/e command worked although I would still like to know how to stay on whichever layer you choose and to continue to create new shapes on that layer without creating new layers.