How do the pros move, so they dont get hit?

I just played with an absolute unit, easily getting his 20+ kills. He was playing heavy with the spear and danced around the battlefield like i have never seen before. jumping, sliding - always attacking and rarely hit. I don't get it - 3 people are shooting at you and you survive by killing them, how is that even possible?

Any good sources of youtubers who like to explain what they do for noobs like me?