SME3009 setup??

Has anyone got any set up instructions for an SME 3009 improved arm. I have not yet received it, but from looking at some on line pics it is confusing. What is the weight on the side for??
The link works just fine for me...but for crying out loud, it's not hard to figure out how to get there the long way:

(1) Go to

(2) Click on "Library"

(3) Scroll down and click on "SME"