When you have added the desired block layouts to your design, you can add elements from the Elements section on the left side of the screen.

Elements are the different kinds of content that you can add to your design. This includes text, images, videos, buttons, surveys, spacers, and social links.

Click on the desired element to drag and drop it onto your design.

After your desired elements have been added to the design, you can add rows to your block layouts. Rows are a way to create and add multiple elements within the same column.
For example, you may want three columns that each have an image element, a text element, and a button.

To add rows to your columns, select the desired element and drag it over top of an existing element in a column. 

Elements can be automatically added to your columns with the cloning feature. This will automatically clone your element and insert it in a row below your current element.

The cloning feature can be used by clicking on the element you wish to clone, then clicking the icon that appears on the upper-right side of the element. This will clone the element and insert it below your current element.

The delete feature will delete an element in a row. This can be used by clicking on an element, then clicking the  icon that appears on the upper-right side of the element. This will delete the element you have selected.

If there are any elements below the deleted element, they will be moved up one row so that the top row of the block has an element.