The ‘Build/Specify’ option will specify the selected object (of the current Window). The ‘Build/Specify’ option will open up a dialog where you will be allowed to choose the objects which are to be specified. If you choose the Edited Only option you will only be displayed those objects which have been edited and not specified (including those which remain so from prior sessions).
The ‘Build All’ option will specify all the Model's objects.
Another way to specify only one object (or an entire Folder) is selecting it from the Folder's window and pressing the mouse's right button. Then, a menu will be displayed with the actions that can be taken, including the Specify option. If the object which is selected is a Folder, then all objects belonging to the Folder will be specified.
Just as in the database reorganization/creation case, these options are only available if working in Prototype or Production Models.