In order to invite your teammate or more users to your workspace, click on your avatar/display pic in the top right of your video dashboard then onto Invite People.
Now you're set to start inviting!
Once you've typed in the email, you'll want to hit enter or add a comma to activate the Next button.
Then after you've added everyone go ahead and click on Next to invite your team!
If you are on a paid plan where you're paying per user, you'll be asked to accept the charges for the new team members (at a prorated rate) on the next screen.
So no worries -- there'll be no surprises on your bill!