The object that you should add to the dashboard to allow users to switch to a different dashboard in the workbook is Navigation.
Navigation objects are used to create links between dashboards or sheets in a workbook. You can add a navigation object to a dashboard by dragging it from the list of objects and dropping it on the dashboard. You can then configure the navigation object to specify the destination dashboard or sheet that you want users to navigate to when they click on it.
You can learn more about navigation objects and how to use them in this article: https://help.tableau.com
/current/pro/desktop/en-us/dashboards_navigation.htm