Which currency pair shall I pick at the beginning?
It is recommended for beginners to focus on one major currency pair and get to know it well. Each currency has its own trading personality, which must be learned. When you are doing well with it, then move on, and trade the other three major pairs, as you see fit. When you are in learning mode, you will have your hands full trying to figure out what to look for, and how to manage your trades enough so that you don’t want to be skipping back and forth between currencies.
Major currency pairs are EUR/USD, USD/JPY, GBP/USD, and USD/CHF.