i'm a rookie

[minnesota ref]

hey guys
i'm a rookie official and i have some questions for you "old vets!" just kidding.
anyway, the other nite i worked with an official who was very stationery and i found myself as the lead/trail official having to constantly be walking from side to side so as not to miss calls for him and myself. my question is should i always be moving from one side of the court to the other whether i am lead official or trail official and whether my partner is stationery or not. should i always stay at a diagonal from my partner?
my next question is A1 is dribbling the ball, B2 is guarding A1. A2 is standing between A1 and B2. there is no contact made between A2 and B2, but when B2 makes any movement left or right in an attempt to guard A1, then A2 makes the same movement to stay in between A1 and B2. is this an illegal screen? sorry for the bad description and i hope you guys understand what i am trying to explain. thanks for the help!