Adding a new Adwords account or manager account (MCC)
In the top right drop down menu, select My subscription.
On the subscription management page, click on the button that says "Link another Adwords account".
You will be take to Google's Authorization pages. Follow the steps until you're brought back into Tenscores and your new account will be listed in the left box on the subscription page.
In order to active a new account, simply select it then click on the "Update subscription" button in the lower right.