Zones can have multiple meanings depending on your job role. For the purposes of my blog, it will be the zones on your SharePoint pages – also called Columns.
When you edit your page to put in web parts, you need to first choose the zones / columns you want.

Then you can start adding web parts into them.

These are the zone options you have.

HOT TIP
To get 4 zones, add a vertical section, then add a 3-column section at the top.

And that’s it! SharePoint A-Z.