You may have used the Drilldown option in SquaredUp v2 to set your own dashboard as the drilldown for users to see when they click on an object or group, instead of seeing the default and often unconfigurable SquaredUp page.
In SquaredUp v3 you can create a new perspective for users to see when they 'drilldown' on an object. SquaredUp v3 uses the concept of Total Dashboard Architecture (TDA) to make every page configurable, and perspectives to show several different views of an object, often each designed for a different audience. In SquaredUp v2 you had a single page showing a generic object view, for example all the information about a server. You now have several pages, called perspectives, each with a different focus on that object. For example, a SQL server will have a SQL perspective, as well as Memory, Disk, and Performance perspectives.
You can then choose to either drag your new perspective to the left of the perspectives ribbon so it becomes the default perspective seen, or with SquaredUp v3.1 onwards you can put the perspective into dashboard mode so that this is the only perspective seen when drilling down, and the perspectives ribbon is hidden.
To create a perspective and set it to dashboard mode to act as a drilldown see How to put a perspective into dashboard mode