Hello,
Yes, install any demo that you like to import header settings, products, posts etc. After that edit the home page or create the new one that you will set as the home page in Settings > Reading and use Page importer to import content of the Default Red home page.
“Import page custom CSS” means that additional CSS that we use for some pages also will be imported to page custom CSS settings.
“rewrite page content” means that if you already have any content on the page and check this option then previous page content will be removed and replaced with the new one that you import. If you don’t check this the content will be imported in edition to existing at the bottom of the page.
If you still need help with this then provide us with WP Dashboard access and we’ll import page for you.
Regards