Use WordPress Database Reset plugin to clear the site content. Then provide temporary wp-admin access.
Create an account via Dashboard (Users > Add new) with administrator role http://prntscr.com/s3rc9m > provide us with username and password via the Private Content area http://prntscr.com/s5mao7 You can use any email for it.
We will help you to import this demo – https://xstore.8theme.com/elementor/demos/marseille01/
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.