XPath help to create custom rules for xml

Hello All,

I am new to SonarQube tool and would like to use scan the couple of xml files (apigee proxy bundle). As part of this I would like perform custom checks in the xml files and for that I need to create custom rules.

As per the help from sonarqube, need to use xpath expression to add the rules. Can anyone help me with step-by-step procedure to write rules for xml.

Also I am using sonar-apigee-plugin-X.X.X.jar downloaded from here. Can anyone help me to how to change the existing rules under this plugin.

Thank you in advance.