I already installed the somalite light version. I´m about to buy the Pro version and I´d like to know what are the procedures to install it in order to not erase the content and basic customization that I already published.
On pro upgrade, the Soma widgets content will be lost as PRO widgets are different and have different class names, rest of the page builder content will be the same. You need to enter the Soma Widget content again. As far as the Customizer customization I think it will be easy for you to add settings again then using a Plugin to keep the settings.
If you still wants to use Plugin to keep Customizer settings, We have a video for Prasoon theme. You can watch this video and see how you can do this. The procedure is same (skip Widget Import) in this
If you want, our developers will help you to replicate the theme into PRO version. You need to create a user for us so that we can log in and edit the customizer and pages.