Turning Left

I have a new downrigger/boat (well, new 2 me ), first time I've ever headed out on my own. Can anyone provide decent advice especially on on HOW DEEP the ball should go? I'll be putting in at Bluffers Park (have a VHF radio if that will help). I hear the fish are approaching the rivers, but I'm not experienced enough to get into any kind of tight quarters with other boats trolling. Thanks?