Android Studio: cannot find "Hello World apps" on emulator screen

Question

I'm new in android development, especially android studio, i try "Hello Word" for my first app, but not found "Hello World app" in my emulator screen. it's look like this:

I search these error, but only event log say: Session 'app': error. Still didn't get any solution even after a lot of searching. Need help please, for my learning.