I Added Another Admin And They Can't Create Dashboards or Users. Their Permissions Aren't As Numerous As Mine.
So at this time only the primary admin (the main owner of your organization's account) can create new dashboards and users. Once dashboards are created though, the primary admin can give others access to the new dashboard so they can add widgets to it and manage it themselves, as long as they are secondary Admin (rather than Read-Only). (So basically widgets but not dashboards.)
We made it this way for security reasons so that new users can't abuse your account. But realize that this could be a real need for certain people so we've added this to our roadmap as a feature request for you.