pipeline, variables and a "prompt" to choose a version

Summary:

Allow administrators, when running a pipeline, to specify which data "version" is contained in a load file—without requiring this information to be embedded within the file itself.

Content:

In a Planning environment, an additional prompt should be available during file upload to specify the target Version. For example, if the user selects 'Working,' the data from the file will be loaded into the 'Working' version. This approach eliminates the need to modify the source file by adding an extra column with the Version value on each data row

How to achieve this "prompt"?

I have following things tested but the overall solution is not there yet ;-(