What should I learn first?

I know this might be a starter question and might get removed but i need to know this – should i stars with the letters ? And for what type ? And what type should i start with and what is the least important? And lastly should I learn all of them – I want to learn japanes to maybe understand japanes music and i have the classic dream of going to japan in the future and I want to know some Japanese if i went there even if not perfect – if you are a mod and think this should be removed please don’t remove it