How to edit my duplicates i have built an apartment complex out of many planes.  So rather than just making 4 planes for a house like this noob normal does, I used shift d duplicate in object mode.  Now in edit mode all of my duplicated planes don't have any vertices,edges, or faces.  After looking online, tried deleting all doubles which I had none.  so I asking for help on what I did wrong using duplicate.  I was in object mode, hit shift d, hit enter, then moved the duplicated plane to a new location.      i am using 2.79b
I think we're going to need more details and possibly the file, because this is likely something very simple.

1st- how did you create the plane? Was it Add>Plane?
2nd- Did you do anything to the plane before duplicating it, like some modeling?
3rd- At the top right corner, it should let you know how many faces, vertices, etc. there are on the selected object in edit mode. When you get into edit mode how many faces does it say are there?
4th- Did you apply any modifiers and duplicate that with the plane?