If you're using the WA CMS, that gets set up with it's own login and everything so you may have to find a way to integrate that with login pages that you built.
ARe "Regular Users' just public users who don't require a log in? If they don't, then you don't need a rule or user level for them. And vice versa. Let's say that they do for now. I'll give you a general outline, but trust me, go through the video tutorials on setting up rules and access levels.
1. Make sure you're capturing the User Level into a Session variable using the login user wizard in SA.
2. Create three simple rules, one for each level - simply to grant access if the user level = 1 or 2 or 3.
3. Create groups that join these rules together in any combination you want - for example, if Admins will also have access to CMS pages and regular pages, you'll combine all three rules.
4. Next, create additional rules that, instead of being based on criteria like the first three rules, are based on a group. It seems like an extra step, but the effect is that you're combining two or more rules into a single rule.
4. Finally, add the rules to your pages - this can be done in bulk. At this point, you may not use every rule that is available, but you will use them as part of a group.
It's confusing I know. I first made the mistake of trying not to use groups. I would write a rule to grant access if "UserLevel >=1" or something like that. In theory, it should work the same, but I often got mixed results.