Connect more Google Ads accounts by clicking on 'Add New Account' over on the Linked Accounts page, and click the Add New Account button in the top right corner.
This button will take you to a Google authorisation page, where you can select or enter the account you'd like to connect to Opteo. This could be a single Ads account or an entire MCC.
Once you've chosen or entered details for the account, click Allow. You'll be redirected back to Opteo, and any Google Ads accounts associated with the new email address will be added to your Unlinked Accounts list.
For an account to appear in your Opteo Account Centre, it must be both connected to Opteo and linked.
To link accounts, simply find the account in your Unlinked Accounts list (the search bar may be handy here) and click the (+) button. When you've selected all the accounts you'd like to link, click Link Accounts.
The accounts will now appear in your Linked Accounts list and in your Account Centre in Opteo.
See more about linking and unlinking accounts here.