Today I'm playing with ARCore on Samsung Galaxy S8 SM-G950F and Unity 3D. Yes, it's SM-G950F, despite this model is not on list of supported devices, it works! If you are looking for a tutorial I refer you to Getting Started with Unity - Google's official introduction.
Here I'm going to describe quickly a problem and solution to it.
XXXXX has stopped. Restart app
XXXXX keeps stopping. Close app
You forgot to install ARCore Service on your android device. Download it and type in terminal:
adb install -r -d arcore-preview.apk