How do I make a page the home page of my website?

In the website's page list, click the star button on the page to make it the default page. The default page becomes the site's index page, so it is the page that opens at your domain.

If the site already has an index page, rename the existing one first (for example to index old) so the new default page can take its place.

After that, connect your domain in the website's Domains tab if you have not done so.