Hi Stephan,
Not to worry. There’s no such thing as a too-simple question around here, and I don’t think yours falls into that category anyway 
If you’re using Keyboard Maestro 8, which you almost certainly are if you just started using KM and have used Prompt With List before, you can use the Trigger Macro by Name action and pass freeform text to the selected macro by including // at the end of your search string. The selected macro will be executed, and anything after the // will be sent to the macro as a parameter, and is accessible via the %TriggerValue% token. Also new to KM8 is the ability to restrict Trigger Macro by Name to certain macro groups or active/enabled macros only, so you should be able to arrange things so that only the macros you want to see for this dialogue are presented.
If you have any further questions, or you don’t think this would quite fit your needs, don’t hesitate to ask