@MatthewB - I perfectly understand your reply to Bob Fitz's comment. So that you understand it from our side, ... We have often been burned by what appears to be a simple request turning into a long drawn-out exercise in pulling teeth from a reluctant patient. Fortunately, your explanation WAS better than many we have seen from new members.
The discussions of tables that you got in response are definitely a good starting point and I won't add to that. I want to address another thing you said.
To control your data's visibility, tables aren't enough. Depending on just HOW much control you want, you will be working towards hiding the back-end structure from those who use the DB. This usually means that you NEVER show your users anything but forms and reports.
The general problem is knowing what to ask. I don't disagree with you. But I can help there, too.
You find out about your topics by searching the forum for "Securing a Database." In greater detail, this will include topics such as "Hiding the Ribbon" and "Hiding the Navigation Panel" but will ALSO include "Switchboard forms" and "Dispatcher forms." You will need to understand how to use a "form filter" or "report filter."
Part of this level of complexity is because in order to limit what someone sees, you can NEVER EVER directly show them a table, query, macro, or any VBA code. When users see those levels of structures, you have lost all control, period. Showing only forms or reports (forms in FORM view, reports in REPORT or PREVIEW view) means YOU can restrict which data elements they see, which PARTS of each table - both with respect to which fields AND with respect to which records.
Finally, your life will be made simpler if you understand "Database Normalization" fairly well. Don't worry, it's not THAT long a topic. But I'll give you a tip or two there, too. You can search this forum for "Normalization" because this IS a database forum. But if you do a general web search, you should search for "Database Normalization" because other disciplines (math, chemistry, psychology, international diplomacy) also use the word "Normalization." IF you use the general web, start with articles originating from .EDU domains - not because they do a better job, but because they are less likely to distract you with ads and are less likely to be discussing a proprietary product that you don't have anyway. But once you are comfortable with the basics, .COM domains will have good articles, too. Just sometimes more cluttered.