Welcome to the Make community!
You cannot individually run a single module if you don’t have example input data values for each required field, which you must input into the dialog box when you manually run a single module. This is because when you run a single module directly, the mapped variables in the module’s fields are null (do not contain any value), as the previous modules do not run and produce any variable values.
Instead, try running the full scenario by clicking the “Run Once” button:

For more information, see these duplicate questions previously asked and answered by other community members:
- Missing Values While Processing Google Forms Data
- Not able to use webhook data
- Make not recognizing value of a variable
— @samliew
P.S.: investing some effort into the tutorials in the Make Academy will save you lots of time and frustration using Make!