Use the App and have it on your phone. Just be mindful of both carry on and checked luggage sizes and weight, they are VERY strict.
Overhead bin space is reserved for priority boarding pass people only. If you dont have priority they wont allow you to use the overhead bin.
At the boarding gate you will scan the boarding pass and they will check your passport, so make sure to have it in your hand when you are boarding.
They have VERY tight turnaround times, and board fast.