Pretty much all fishfinders are going to vary from unit to unit, black white color, dsi, transducer mounting method, etc...the best way to learn is time on the water. A good place to start is in the bay. Start out in shallow water metering known objects, like sand, rocks, grass, kelp and note what it looks like. Look for baitballs and again note what they look like. After time you will start to figure it out. Main thing is to pay attention to everything around you and watch your meter, and you will eventually be able to tell the difference between hard bottom, soft bottom, rocks, finbait, squid, structure, interference, turbulence, thermoclines, suspended objects, sealife....
Good luck out there! Figuring it out is part of the fun!
