[OSU]

I have GWX 3.0 and the ACM-GUI Reloaded mod. I have been trying to get the hang of manual targeting for the longest time, and I just can't seem to get it. The manual for the ACM-GUI mod for manual targeting is no good. I was just confused by that. I know how to use the wheel thingy. What I specifically want to know are what are the two AOB gauges for in the attack periscope/UZO/TDC? I know how to set the speed of the target and the range, but I need to know what the other two gauges are for. When I see AOB, does it mean the target's angle off of MY bow, or my angle off of the TARGET'S bow? And that other gauge with the thin needle. What exactly does that do? Any help would be greatly appreciated.