How can the user enter their own value in Data Mashup?

Hi,

please see the link below:

https://help.sap.com/viewer/cea15f900ca04c4faa35d3044577fe27/1902/en-US/186b3de4763d1014bdd381a74921cf5f.html#loio98b5a38f6d8e1014b274e8d5e6beb54c

It is about the creation of a Data mashup. In paragraph "Create Data mashup" you read this:

"To preview the mashup results you may have to manually add a value to the input field of the mashup in-port or user input. To do this select the building block and under properties, enter a value. In the runtime version, these values will be replaced automatically by either the parameter taken from the screen out-port or by the user entering their own value."

Could somebody explain me how the runtime version works please?

How can the user enter their own value in Data Mashup?