First please install and activate Elementor and Coursector Theme Elements for Elementor plugins before you proceed.
Once you get required plugins installed. Please follow below steps.
Create a page or edit an existing one.
Click “Edit with Elementor” button to open Elementor Page Builder.
Click “Add Template” button and scroll through “Pages” section.
You will see popup modal window. Click “Pages” tab to see a list of all page templates. You can filter only Craft templates and select demo page you want to import and click “Insert”.
If you have experience Coursector template issue with Elementor library. Please make sure you update the plugin “Coursector Theme Elements for Elementor” to v1.9