You can add more User/Channels to the Standard Plan at any time, including during the free, trial period.
1. From the menu, click Settings
2. On the Settings page, click on Manage Your Subscription
3. On the Manage Subscription Page, click on Add or Remove User/Channels
4. Select a number of User/Channels to add. You can select additional User/Channels more than once.
Note: If it’s still within the free trial period, you will not be charged until the the trial period ends and you have added your credit card information.