Best thing to do is read the manual that came with the comwifi and the app, all you need to know is there, we update the routers IP address in the app so it can always connect. Notifications are instant, push is handled by the server as are emails, no need to understand the ins and outs of how it is done, all you need to know is it works, we handle the IP updates and the notifications.
I do t want to sound patronising with the answer above, but everything is detailed in the manuals, follow them and it will work.