kb here  i was watching a fishing show   and this guy was at front of boat dropping a drop shot rig   and you could see the bait dropping    i have had hummingbirds and now have a garmit 240  on tholling motor and a 240 on dash  and i have yet to see my line or bait in finders   how do i set finder to do this   kb

You will have to read the owners manual.

Automatic settings should be turned off and adjust the sensitivity until you get a thick line above the bottom of the units screen, this is the bottom of the lake. If you adjust the sensitivity down you should be able to see your bait and fish hit it if you are in the sonar cone.

I use an Eagle Fishmark 320, and I can watch my jigging spoons sink from 2 or 3 ft. on down to 35 or so, and that's with the automatic settings on.