Softly is developed for only WordPress CMS so you need to have WordPress installed on your server or local pc to run run Softly Software Listing theme.
You have to install WordPress before to use softly theme. To see WordPress installation please follow the link bellow as per your requirement.
Or you can check this Codex tutorial to know all about WordPress Installation.
Install WordPress on Cpanel Server
Install WordPress on cpanel is the most easiest way and you should try this. If you want to see details documentation then I will recommend you to read this article or you can see YouTube video from bellow
Install WordPress On VPS
This will be complex process and if you are not expert with Server Administration or at least linux command you should go on cpanel server.
For details documentation and articles please follow this link