Put your mouse over the left side of the project window to show the variables. The target speed variable is the target speed of all the boids speed. The resolve variable is the speed each boid reaches the target speed. The range variable is the distance between a boid another boid it reacts to. The seperation variable changes the seperation between boids. The cohesion variable is the amount the boids flock together. The alignment variable is the amount the boids in a flock go in the same direction.
Thanks to griffpatch for the tutorial on YouTube.