To add an icon to the panel

1. Drag and drop an image panel onto the builder. A sheet with configuration options will automatically slide in from the right side of the screen.
2. Click on the icon in the panel.
3. On the right-side of the configuration sheet, you will find  Display -> Image source.
4. From the image source drop down, select  Icons.
5. Select  Icon Type -> Outline / Solid.  Click to select an icon from the list.
6. Click  Done.

To edit a panel icon

1. Double click the panel in which you want to edit the image.
2. Or single click to select the panel in which you want to edit the image and then click  Configure  option, present in the toolbar on the top center of the page builder. 
3. Using either of the methods in step 1 or 2, will open up the slider menu for panel configuration.
4. Click on the image/icon to be edited.
5. On the right side of the panel configuration sheet, select  Display -> Image source -> Icons.
6. Select  Icon Type -> Outline / Solid.  Click to select an icon from the list.
7. Click  Done.