Please follow the below video or the the following steps to configure Performance Settings

• Go to Appearance > Customize > General Settings > Performance Settings
• Enable Lazy Load to allow the lazy load of featured images to enhance the load time of your website
• Enable Lazy Load of Content Images. Blue is enabled.
• Enable Defer JavaScript to strip tags to improve the page download speed.
• Enable Ver Parameters from CSS and JS file calls to improve page load time.
• Click on Publish