How to edit DMN variables

I have created a sample DMN diagram using the online javascript tool and I’m trying to import it into the RedHat KIE server but I get this error:

CD1D716F44FF4CDE997FD2B54BC2FE11 2019-12-18 23:50:25,324 org.drools.compiler.kie.builder.impl.KieProject [https-jsse-nio-] ERROR: Unable to build KieBaseModel:promotion-kie-base
DMNKnowledgeBuilderError [message=Decision node 'Calculate Credit Account Points' is missing the variable declaration, namespace=, dmnMessage=Message [id=0, level=ERROR, path=null, line=14, column=-1
   text=DMN: Decision node 'Calculate Credit Account Points' is missing the variable declaration (DMN id: CreditAccountCalculator, A variable declaration is missing) ]]

It says I’mmissing the variable declaration. I can probably edit the XML myself and add the variable declaration, but I was wondering why is the dmn properties panel not showing the variables options? It only shows the id and the name of the element.
How can I edit the variables through the javascript dmn modeler?