How to configure push notifications to be sent to my unity application from my server?

Question

Hi,

I was going through your documentation on Push notification. I have successfully confiugured my unity application on Google play and Google Developer Console. I have recieved notifications from your sample app using SendMessagetoAll and SendMessageToUser. I have also sent messages to your sample app from APPHQ console. All of this is working quite smoothly. I would like to know how to configure messages to be sent from my own server usig php code. Is there any documentation related to this?

Thanks,

WorldCricMan