Good day.
Please read 
this article about minimal code sampe for screen sharing.
To record screen share stream, you should add 
record: true option to createStream() function call:
	
	
	
		Code:
	
	
		session.createStream({
  name: "mystream",
  display: document.getElementById("screensharing"),
  constraints: constraints.
  record:true
}).publish();
	 
 Please read more details about stream recording 
here
If you want to stream a micropohe, you should list all microphones available to browser
	
	
	
		Code:
	
	
		    Flashphoner.getMediaDevices(null, true).then(function (list) {
        list.audio.forEach(function (device) {
            var audio = document.getElementById("audioInput");
            var i;
            var deviceInList = false;
            for (i = 0; i < audio.options.length; i++) {
                if (audio.options[i].value == device.id) {
                    deviceInList = true;
                    break;
                }
            }
            if (!deviceInList) {
                var option = document.createElement("option");
                option.text = device.label || device.id;
                option.value = device.id;
                audio.appendChild(option);
            }
        });
    });
	 
 and then choose one to stream audio
	
	
	
		Code:
	
	
		var constraints = {
  video: {}
};
constraints.video.type = "screen";
constraints.video.withoutExtension = true;
constraints.audio = {
   deviceId: $('#audioInput').val()
};
session.createStream({
name: "mystream",
display: document.getElementById("screensharing"),
constraints: constraints,
record: true
}).publish();
	 
 To capture system audio in Chrome browser, you should set 
shareAudio switch while choosing object to capture
Please note that microphone should not be used in this case to escape echo. Also, system audio can be captured only for entire screen or Chrome tab, but not for Application window.
Please read screen sharing details 
here.