retrive value from current page inside expression builder

Summary:

Hello,

I want to set a customization ( inside a HTML Markup ) visible only to a set of person.
This customization is made to all change orders pages.
To make this i'm using the “show component” from the “component
properties” of the HTML Markup and I want to set this visible to the
user set in the field Assigned To of this page.
How do I retrivee the value?

this is the setup, in red the customization, in green the value I want to retrivee:

This is the expression bulder open from the Show Content:

Under the Page Parameter I don't find any value.