I recently purchased my first plane an ARF and a 6EXA radio. Obviously I have never built a plane before and therefore have never installed servos. I have a rectangular molded plastic piece that came in the box. It looks like it has servo arms but these are "fatter". It looks like they are to be cut from the molding plastic skeleton surrounding them as if it were from a plastic model box. Anyway, the molded plastic part in question contains three triangle looking pieces within it that each have three holes and two straight pieces with 4 holes? What is all of this for?

Secondly, my goldberg eagle II arf asks for a servo with a straight arm and says that it "must" look similar however, the closest arm to a straight arm that came with the radio has 4 arms. Do I need to cut off two of the arms or will the 4 arm suffice? Now, the servo in question is for both ailerons. This question is for all servos in general. Should I try to center them by range of movement as much as possible before placing arms on. This may seem like a dumb question but like I said, I am ignorant about these things.

Lastly,
The manual writes about the 1,2,3,4 on the servo arms and says that the numbers represent how much off of 90 degrees they are. I don't quite understand what this means. If I have a arm with four extensions on my servo and point the one with 3 on it towards me does that mean it is 3 degrees off of 90 degrees. I don't get it. []

Thanks a bunch!!!