http://www.dual-boxing.com/forums/in...ard&boardID=10

and the stickies at the top of this forum will answer any question you might have like that in the future. If it pertains to literally just starting out multiboxing, it's probably in the stickies. Try reading before you post, it's likely someone who came before you has had the same issue(s) and asked about it.

/assist or the F key when you AREN"T boxing selects your friendly target's target....that's basic gameplay.