A Yasuo Guide for Dummies

Passive: You have a shield that you get from walking. You also have doubled bonus damage called crit chance.

Q: A basic attack with 100 extra damage.

W: Blocks every ability in the game.

E: You can dash shit-ton.

R: Keep enemies unable to do stuff for a couple seconds and do damage. Enemies gotta be airborne.

For a full extensive guide on Yasuo, I have a real good one found here.