You have to create the script to call it.
After that you can use script.turn_on or call the script directly as a service IE script.your_script_name_here.
In the case of that blueprint, you need to create a script for that blueprint with your variables, then call the script that you created.
Script ui editor, create a script from blueprint, select that blueprint, fill in the blanks and remember the name.
Thanks! That is a pity. I might just make a trickier automation blueprint instead with triggers, conditions and more actions as inputs instead. Or group it in a package.