You may have signed up for a 1-site plan, and now you need to add more sites. This help article describes how to upgrade your current active plan:
- The current active plan is shown under the WordPress dashboard interface:

- To upgrade your plan, please click "Actions" and then "Upgrade Plan" under the dropdown menu:

- Scroll down a bit to see the "Upgrade Your Plan" widget, and select the new plan:

- Click "Upgrade" in the confirmation pop-up:

- You will see the "Upgrade Successful" pop-up, click "OK":

- After the new environment is built, that is, after the upgrade is performed, you will see the new plan and the available sites:

That is it! You can start adding more sites.