Android starter

Hello everyone.
I'm just starting on the Android world and I'm kind of lost. I'm able to find lots of documentation, but I'm struggling to connect the dots from an architecture perspective.
I want to start developing an app that would basically have two different modes, one for clients receiving notifications, and a second for the suppliers pushing the notifications. On top of this I would like to have a web-site with a CM to manage what's happening between client/suppliers and also to allow for some data mining in the future.
What's I'm struggling to understand is what i would need from a systems perspective. Create one app with 2 different users groups, create a web-site with a DB and a CM (like wordpress) and then connect the app to the web-site to monitor the activity. High level this seems not that complicated, but when i start detailing it is a lot to digest... is there some kind of architecture guidelines for app linked to web-sites/DB? What kind of servers and software recommended, services that i would have to buy, etc.
Any pointers would be greatly appreciated!!

Kind regards,
nuno