Note: If you want to edit a new site, you have to unpublish the current website and make your new site as your primary website.
Under My Sites, click the [...] Ellipsis Icon on the top-right corner of the website to unpublish the current site. Click Unpublish Site, and then click Yes, Unpublish to confirm.
Under My Domains, click the [...] Ellipsis Icon of the website that you want to replace as your primary website, then click Replace Primary. In the pop-up window, select the domain of the new website in the New Primary Domain list, then click Replace Primary. You can also click the Domains tab under My Sites to perform the necessary steps mentioned.
You can now edit the new site that you wish to manage.