AWSD or Arrow Keys "Velocity?" controls whether or not the player will have velocity or move at a constant rate. Speed is self-explanatory. I recommend setting it to 1 when you have velocity on and 6 (aka the max slider range) when you have velocity off. Diagonal Multiplier controls how fast player moves on diagonals (test out values and see what you like) Friction only applies if "Velocity?" is set to 1, as there's no friction for moving at a constant rate. Setting friction to 1 means the player won't slow down. Setting it to anything below 1 will make the player speed up rather than slowing down, which could be a cool effect, but it's up to the user.
Order for @2016s4m29 There's a comment inside that basically goes a little bit more in-depth on how the diagonal movement variable works, but other than that, this is the order!