the Get Unit is a Session Unit and it's used to retrieve the values stored in the Global Parameters. It is also a Content/Operation Unit.
You can find more information about the Get Unit in this article of our wiki:
In order to retrieve the desired Attributes of the user, the Get Unit setted as Operation Unit must be linked to an unit of an operations chain. In order to follow a flow, the Units of the operations chain must be linked by OK Links.
In your case in fact the Get Unit and the Selector Unit are outside the Page and the Selector Unit is not reached by an OK Link (i.e. the Ok Link outgoing from the Input Collector Unit). The Selector Unit is not executed.
In order to solve this problem you can try to cut the Get Unit and the Selector Unit and paste them to the page. In this way in fact the units will be executed during the load of the page.