There are a few ways to upload themes to WordPress, you can read about all of them here, but one simple way is:
- Download theme and and create a ZIP file of the theme on your local computer.
- Inside your WordPress admin menu (standalone) or network admin menu (MultiSite) go to the Install Themes panel and click on "Upload".
- Choose your ZIP file and press "Install Now".
This theme utilizes the Theme Updater Plugin to push update notifications directly to your WordPress site.