it all depends on the servo, you just have to find that bit out when you get there... mine is 90 for extend and 10 for retract...

as to the code, you should slow down and read it, instead of thinking it is gibberish...

that code is saying if num_servo's is defined, we are going to define servo_0 to pin 5(software), if the number of servos is greater than 1 we are going to define the second servo, Servo_1, to pin 4(software).

let me find it again and i will post a link, it was page 10 if i remember correctly... i'll edit this post with the appropriate post

http://forums.reprap.org/read.php?151,246132,page=10

The posts are by JWD