I am new to Alteryx, testing it out for our company. First post!!
Drop down troubles:

I am trying to pass a variable from a drop-down to a filter, allowing the user to pick a city to run the report against.
The drop down populates correctly in the wizard:

The default is set to Alexandria_LA.
I noticed I am not given the option to set the expression. (I assume this is where the issue resides.)

I have the filter set as a custom filter with the intent of bringing forward the value from the drop down.

It must be a simple oversight. Any suggestions would be appreciated.
Thank you in advance,