Start test from home screen


I just started to use Appium.
I want to do simple, quick test. I want to got to SMS from my phone main screen, write something and send message.
Problem is that I don;t know how to start test without actual .apk file, just from my home screen.

I tried to use some .apk file and in desired capabilities in activity i tried ‘.homescreenactivity’ (or something similar, just found it on internet) but without effect.
I have tried also to start from apk and then go with self.driver.back() but this don’t work either.
Can you tell me how to do it?