Your theme demo is not imported completely. You are getting the error of Revolution Slider Error: Slider with alias home-page-boxed-slider not found because Revolution Slider demo data is not installed properly. You can check it from the WordPress dashboard via a click on Revolution Slider. Kindly understand this error alias home-page-boxed-slider not found because alias home-page-boxed-slider is not installed. You can create a new slider inside the Revolution Slider or you can install home-page-boxed-slider again from your ThemeForest theme or another theme zip or rar folder.
Go to Revolution Slider and click on manual import.
Select Revolution Slider demo data ( zip file) and install. The Revolution Slider demo will find inside the theme zip file. It will definitely work. If the error occurs then comment to me.