You should hear audio coming from your speakers or headphone! Congrats on making your first call via WebRTC using Asterisk!
If you attempt to use WSS instead of WS as your transport, note that Chrome and Firefox will not allow you, by default, to connect, using WSS, to a server with a self-signed or otherwise invalid certificate. Rather, you'll have to install a signed certificate into Asterisk or import the server's self-signed/invalid certificate into your browser's keychain, which is outside of the scope of this Wiki. As a workaround with Firefox only, for testing or development, you can open a separate browser tab and point it to Asterisk's HTTP server's TLS port, e.g. https://[your asterisk:8089/ws, and confirm the security exception.