In the settings section, click Dashboards in the column on the right hand side to access the list of current dashboards. You can add new dashboards and remove existing ones. However, the main dashboard can never be removed: there has to be at least one dashboard associated with your subscription.
Alternatively, you can also scroll down to the list of dashboards on the company overview page (which is the first page that opens when you click Settings on your dashboard).
When you edit the dashboard, you have the option to configure a house style for that dashboard specifically. This overrides the company house style in the page designer, which is configured on company level.
You can configure exactly which users have access to a certain dashboard. You can do this when you create the dashboard, but also when you edit it. Under the label Users allowed to use this dashboard you see all currently configured user accounts. Check the users that should be able to access the dashboard.
The same permission can be configured from the user management page: there you can configure what dashboards a user should be able to access.