How can I learn basic Italian phrases before leaving for my trip?
If you have never learned Italian, first try using apps like Duolingo to help you with grammar and pronunciation.
Next, I suggest watching your favorite movies and TV shows in Italian. The ones you know by heart. When you know what the movie is about you will start to understand some words. Netflix and Amazon Prime have a bunch of movies with Italian as the original language as well. Just search Italian movies.
Another thing you can do is listen to podcasts that are for beginners. This podcast I recommend because you are learning along with another student. It's great for pronunciation, learning salutations, and most importantly learning how to ask for directions.
I hope this helps you learn a few phrases in Italian before you go.