In admin, Go to wp-admin/themes.php and click button Add New
In form search theme, searching “knirpse”
After that, You
Install from WordPress
Login into your admin section in WordPress (http://your-site.com/wp-admin)
Go to Appearance – Themes
Click Add New and Search
Input Search to find “knirpse” click Install Now
The theme will be installed
Activate your theme
Install Using FTP
Log into your hosting space via a FTP software (eg. FileZilla)
Upload theme folder (unarchive theme_name.zip) to wp-content/themes in your WordPress installation
Login to your admin section in WordPress (http://your-site.com/wp-admin)
Go to Appearance – Themes
Activate your theme
Important: After activating the theme, you will be prompted to install and activate the required plugins. Those are essential plugins and theme can’t run without it. Read more about plugin installation here.