The app selector is located on the record editor within the Fulcrum web app. The label for the app selector will be the name of the app that you are currently viewing the data for.
Changing what data you are viewing
To change which app you are viewing data for you can click on the app selector to view a pick list of the apps and repeatable sections within those apps.
Within the pick list, apps have bold text and app icons, if set. The text under the views are the saved views you have set and the options under repeatable are the repeatable sections within that app.
Clicking the name of another app will load the data/records contained within app into the record editor.
Clicking on the name of a repeatable section will load all the data contained within that repeatable section within the record editor.
Clicking a saved view will load that filtered data view for that app within the record editor.