OK, got it figured out. Storage of buildings is a temporary feature only. Buildings can only be "set aside" while rearranging your town. Enter "edit" mode and select building to store and use the down arrow into the storage box. Once you exit the "edit mode" all buildings come out of storage.
Hint the word temporary, meaning you put everything in storage while you're rearranging and then take it back out and place it in your town before you save it. It's not permanent storage. Also, I would asume the feature is available at level 5 or 6 when you get the customization options of your town. To access it enter edit mode, and tap the four green arrows in the bottom left corner of the screen.
If you have any other question, please let me know.
Pls help for temporary storage it is not work properly. I have enter edit mode or click the erase mode on and select the building than save but save button disabled. So what can i do pls suggest and help
In the "big edit mode" you can only save with decorations put into storage. All community buildings (CBs) and all houses must be put back outside / stay outside. So, either you have time for it, or you work in smaller portions.