You got the right theme Cosmics Spa are childs themes of hantus theme. You can customize it by customizer settings Or you can import demo by follow the following steps
Install & Activate All recommended plugins and then navigate to Appearance >premade demos >Import Demo Data. It will import all the demo content.
In WordPress dashboard go to Appearance and click on Premade Demos.
After clicking on Premade Demos you will click on Demo Import Button.