Hi the error is showing that the ionic was not installed properly in your setup .
Please follow this course again and try to setup ionic in a different folder and make sure each module installs well .
refer : https://wplms.io/course/how-to-install-ionic/
when i want to create a reverse client ID, google asks me to add a sha-1 signing certificate and the package name. for the name of the package google says it is in the file AndroidManifest.xml.However is the file AndroidManifest.xml or how to have the reverse client ID ? http://prntscr.com/jlzlip