Can you tell us what you do see in your Tools menu? You may be looking in the Application Menu, where things are laid out differently.

You are going to find that most help articles were written before the Menu Bar was hidden and replaced with the AppMenu button. As some kind of cruel joke the developers decided it would be fun to move the menu choices all around in the AppMenu tree to confuse things.

If you use the Tools option on the Menu Bar the Add On choice is still there.

Press the alt key if your menu bar is not showing.

Add ons is its own choice when using the AppMenu button so it is no longer under Tools there.

I suggest that you turn your menu bar back on so the help articles match what you see and it is much easier to use anyway.

Press the alt key. From the Menu Bar select View-Toolbars and turn the missing toolbars back on.

Mail & Newsgroups Address Book Account Settings Options

The menu bar is showing. But the add-ons option is not there. In the help menu there is even an option that says "restart with add-ons disabled" but add-ons are no where to be found.

Ok. Figured it out. I clicked the "restart with add-ons disabled" and it actually enabled them.