You need to select something to edit within your InDesign document before you can edit it. I suspect that if you select any element placed within your document and return to the Edit pull-down menu, you'll be able to see many more options for how you can edit that selected element.
For what it's worth, I don't know this because I'm Rhodes Scholar-bright about working with Adobe InDesign. I believe I quickly recognized your issue because I've screwed up that way before.
Menus are context-specific. Without anything selected, those unavailable commands have nothing on which to operate. The ones that aren't disabled are available because, for instance, there's something on the clipboard available to paste, so the Paste command is active. If the clipboard was empty, Paste too would be unavailable.