Ionic-cordova: How to use cordova plugin in Ionic 1 (error: Plugin is not defined )

ionic-v1
1

I heave installed the RadaeePDFPlugin (https://github.com/gearit/RadaeePDF-Cordova) cordova plugin in my existing ionic project with this command:

cordova plugin add https://github.com/gearit/RadaeePDF-Cordova.git

After that, the installation created a folder inside plugins with the name of:

plugins/com.radaee.cordova/

the documentation (https://github.com/gearit/RadaeePDF-Cordova) says to use the plugin with this command:

RadaeePDFPlugin.openFromAssets(
    {
        url: "Test.PDF", //the pdf name
        password: "" //password if needed
    },
    function(message) {
         console.log("Success: " + message);
    },
    function(err){
        console.log("Failure: " + err);
    });

but after running the application had this error:

ionic.bundle.js:21157 ReferenceError: RadaeePDFPlugin is not defined
at Scope.$scope.login (controllers.js:19)
at fn (eval at compile (ionic.bundle.js:21972), :4:273)
at ionic.bundle.js:57514
at Scope.$eval (ionic.bundle.js:24673)
at Scope.$apply (ionic.bundle.js:24772)
at HTMLButtonElement. (ionic.bundle.js:57513)
at HTMLButtonElement.eventHandler (ionic.bundle.js:12098)
at triggerMouseEvent (ionic.bundle.js:2865)
at tapClick (ionic.bundle.js:2854)
at HTMLDocument.tapMouseUp (ionic.bundle.js:2927)
what the correct way to use this plugin?