This is a plugin to add a tool in the Customize preview to check the responsiveness of your WordPress website.
No options needed, just install and activate it, then click on “Check responsiveness” on the plugins page, or go to Appearence => Customize => Responsiveness Check
Upload the entire
wordpress-responsive-check folder to the
/wp-content/plugins/ directory or install it using the usual installation button in the Plugins administration page.
Activate the plugin through the ‘Plugins’ menu in WordPress.
After successful activation you will be automatically redirected to the plugin global settings page.
All done. Good job!