Ok I've been reading the book and playing with my fishfinder. I can tell hard and soft bottoms and find weeds most of the time.

  One thing in the book that I was wondering about.It says The "ping" if you will is cone shaped and gets wider towards the bottom.In 10 feet of water the cone is 10" in diameter.Most of the lakes I fish here it's hard to get 10 feet deep in most places.If I ping a 10" bass in 10 feet of water does he take up the whole screen or what?Or am I misunderstanding the instructions somewhere? Thanks.

PM sent, too much detail to explain here.

The cone they are referring to is shape of the transducers sensitivity to returns from the bottom. An object in the cone will reflect more of the trasnmitted pulse and is represented on the screen. An object outside the cone will return a weaker signal and may not show on the screen at all.  A 10 inch fish 10 feet down will reflect much more energy (ping)  than the same fish 100 feet down. So it may be displayed as a larger fish. Smarter FFs can allow for the greater distance to the target and indicate about the same size fish for either the 10 ft target of the 100 ft target. You really don't care how they do this. Most FFS have 3 or 4 sizes of :-/ fish symbols for their display. A salmon and a whale would both be displayed as the largest size they have.  :-/ Keep an eye on the FF, it is one of the most usefull tools you have on the boat.