This challenge took much longer than expected but I added a lot of information below in case someone else was struggling with creating a dynamic list and being able to see your results.
This was my first time using the interface tools. I had to add them back into my palette. This was also the first time I looked at solutions, in addition to outside research, to figure it out. Here is what I learned. I overdocumented for both myself and anyone else who struggled so much of this is basic but I hope it helps someone!
1. To look at solutions saved as apps, you need to open them from File Open Workflow, not just open it from a download by double-clicking or you are looking at the app, not the workflow behind it.
2. The Alteryx solution used manually set values (had to enter all possible position #s by hand) to generate the list of dropdowns. While this works, it is not dynamic. To make it dynamic, there are options to either create a list as an output and pull it back in or do something similar to what I did. You need list of all unique position # and have it be the column headers (row 0, not row 1).
3. You will not be able to see your results in a typical browse tool using an app. You either need to output the data for review OR you can use browse and turn on results to user. Otherwise, you will get "There Were No Output Files".
To do this, you need to find the Interface Designer- Properties (which I had trouble locating but it is to the far left, next to the "traditional" configuration window. Click on settings and then "On Success - Show Results to User" and select the browse windows you want to see. I had to rename mine to figure out which ones I wanted to see.
4. You cannot just hit run, you need to run as analytical app, next to the run button. This will open the app where you can select the position #. Hitting Finish will open the results with tabs for all the browse outputs you wanted to see. (I know selected 122222 here, not 333333).
I did a double join rather than append but it works. I hope this helps someone!