Push to send specific User.

Push to send specific User. 

I'm following the blog sarina push to send the application. Worked properly but it does not teach how to send to a specific user. 

Anyone know how to say? thank you 

http://blogs.embarcadero.com/sarinadupont/2014/04/17/sending-notifications-from-baas-enabled-desktop-apps-to-your-mobile-clients/
http://blogs.embarcadero.com/sarinadupont/2014/04/17/sending-notifications-from-baas-enabled-desktop-apps-to-your-mobile-clients