Jetpack Compose and ViewModel to handle state

When using Jetpack Compose, ViewModel is the primary means of exposing screen UI state to your composables. 

ViewModel codelab

I'm currently studying how the ViewModel works in Jetpack Compose so that I can include a ViewModel in my own Android apps. I then move on to testing apps and navigation to a new screen within one activity. I've been stuck on these topics for a while and am reviewing my own documentation on this.