Knowledge Models in the Parked & Blocked Invoice app
The App comes with one Knowledge Model (KM) called “Knowledge Model - SAP FI & MM”.
Note
The KM is pointing to the Base KMs stored in the Marketplace. You will not be able to update the Base KM. You can overwrite the PQL, names, formatting, etc. using the KM’s visual editor. If you prefer working with the YAML Editor, copy the IDs from the Base KMs (see final model) and overwrite them in the KMs that are accessible to you in the YAML Editor.
To start with, go to the AP KM package and open the Knowledge Model (it should be the only asset inside the app). Go through the Variables section in the View mode and validate whether the input used for the variables is correct. To view all variables in use, navigate to the Variables section of the KM. For the apps, only non-auto generated configurations are used, so you can disable the auto generated definitions 
.
Tip
You can see which objects refer to a variable by copying the Variable ID, going into the YAML Editor’s View mode (“Final Model without variable replacement”) and search for the copied variable.