The Divi Program has three main building blocks:
The Blue block is called a Section, such as the header, the body, footer, etc. but you can also make a sections within the body, such as a special offering of some sort, etc.
The Section contains Rows, which are Teal Green and can contain a variety of configurations of Modules
Modules (grey) are blocks such as Text, Images, Buttons, etc. chosen depending on the preferred use.
To add a Section, Row or Module, you click on the plus sign of the correct type.
If needed, you can drag those into where you want them, sometimes an easier task using wireframe view. (click the purple dot at the bottom and the views should be shown on the far left.)
Or you can duplicate any of those by clicking on the icon with “double pages”
If you have multiple modules in a row, the tablet or mobile view will read across the row, then go to the next row, etc.
So you can add a Row to fit your need, then use the modules and add another row. In tablets, mobile phones, etc. the top row will show left to right, then left to right on the next row devices that cannot show the desktop view.
If you change your mind, you can change how many modules you want in a row by clicking on the “jail bars” symbol in the settings area..

Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Below is from the wirefrme view for the Gathering Boutique
