You can install this theme by uploading the theme zip file in WordPress admin panel.
Go to Appearance > Themes > Add New > Upload Theme). You won’t lose any of your content (posts, pages etc.) when you activate it.

Installing Theme

Go to Appearance > Themes > Add New
From top, Click on Upload Theme
Choose the ZIP file you’ve downloaded & Click Install Now
Click on Activate to activate the theme

Activating License Key

If you are using premium version of the theme, make sure to insert the license key so that you can get future updates as well as view the dashboard page to get access to several features including importing any starter templates.

You can find the license key on your email address which you’ve used to purchase the theme. After activating the theme for first time you will be redirected to the dashboard page where you can enter the license.