Working with apDiv Tags

I'm not going to pile onto what was already said about the right or wrong way to use them, but APDivs are still very much within the programs capabilities...

APDivs on old sites still function identically to how they had in past versions of DW, even though the button that generated them is long gone, you just have to be in Design View.

1. Go to Window > Toolbars and ensure you have Document active.
2. Then switch the Live to Design by clicking the small triangle in the Document Toolbar

Or...

1. Toggle back and forth between Live View and Design View using the keyboard shortcut Ctrl + Shift + F11

Even though DW dropped the buttons for creating them, it still has all of the editing functionality for APDivs within the Design View editor.

1. When you click inside your APDiv, it will highlight in dark blue.
2. Click an anchor to drag the size of your APDiv (two-way arrow icon appears), or click and drag the blue line to move it around your page (4-way arrow icon appears)

APDivs are a thing of the past.  Adobe saw fit to remove them from Dreamweaver more than 10 years ago.  They were never mobile-friendly and a really bad way to build web pages. 

If you can code manually with HTML & CSS, you can still position elements absolutely for special uses cases but it's not recommended for primary layouts.  Absolute positioning removes content from the normal document flow.  Depending on the user's device & settings,  this can lead to unwanted results that make the site unusable.

For best results, create custom layouts with CSS Flexbox or CSS Grids.   It's much simpler, no positioning or floats are required.

MORE CODE TUTORIALS:
- https://www.w3schools.com/html/
- https://www.w3schools.com/css/
- https://www.w3schools.com/js/

- https://www.w3schools.com/boostrap/

Hope that helps.

I don't know if Dreamweaver shows absolutely positioned divs correctly in design/layout view but if you view the page in a browser they should be in the correct position. Having said that using absolutely positioned divs for the main structure of a web page is unstable and that's not the worflow which should be used. Absolutely positioned divs can be useful in certain situations and should only be used very sparingly.