PLEASE....help me understand what this means

[Sal Giaco]

Originally posted by Tim C

..."B" -- The starting position for the BU with runners on certian bases under certain mechanic systems. Located in a position part way between the back of the pitcher's mound and second base in a line disected by an imaginary line that runs approximately from the inside line of the left handed batters box to the first base edge of the second base bag...

There's got to be a way to simplify this positioning for novice umpires. I've been doing this a while and had to reread it a couple times. Probably just me though