The Free plan is limited to one user.
Choosing the Free plan after your trial
If your 14 day free trial has ended and you decide not to choose a paid plan, you can always choose the Free plan. All you have to do is hit the button in your account’s billing section and you can continue to use the features available on the Free plan completely free.
You'll need to remove any excess of widgets, dashboards, users and screens you've added during your Pro trial.
Downgrading from a paid plan
If you want to downgrade from a paid plan to the Free plan, any additional dashboards, users and screens you've added will need to be removed.