new to trolling

went out to spoils island yesterday morning jigging. didnt do to well. we saw alot of people trolling and getting fish where we were jigging. tried trolling reef runners to no avail. what are the guys trolling and how far back. also is there a certain speed you need to go. some guys were in eight feet of water and others were in sixteen or deeper. is there a depth we should be trying to get our lures in. are planner boards necessary?. there were so many boats out there i know some boards must have got hit

thanks for any info you can share

new to trolling