After you purchase and load the SOS plugin head to the left side panel and click on SOS.
You can import the 5 sample layouts SOS provide in the json file that comes with the plugin or you can build your own layout from scratch.
Layout 1
Layout 2
Layout 3
Layout 4
Layout 5
When beginning your design for the modal you need to save your new layout as Layout > SOS Layouts
If you want to use one of the sample layouts you then select Choose a Premade Layout, the SOS layouts will be available.
IMPORTANT – If the loading symbol hangs for ages head to Permalinks and save.