Hi MAT1C, and welcome to the AC Forums.
You probably want Google's official developer fundamentals page here:
http://lmgtfy.com/?q=android+processes&l=1
Everything you need is on that page, and you could maybe skip to the Processes and Threads section, the Component Lifecycle section (there's a nice flowchart for you there) and the Processes and Lifecycles section. Bear in mind that Processes on Android are different from most other operating systems, and it all ties in with threads, activities, services, receivers, broadcasters, and intents.