I'm assuming that you are using the full version of Acrobat? What sort of edits are you trying to make? I think if you're unsure about making changes, it's a good idea to make a backup copy of the document before you dig in. That way, if the content is altered in a way that you didnt intend, you can revert to the saved backup. But, if there's a specific editing tool or technique that you need help on, please let me know and we can take it from there.