The approach
Start with the right question.
Learn what your transducer shows and where the display places the bottom and suspended returns.
In practice
Make it useful on the water.
Match marks with depth, position and actual casts before claiming you have found feeding fish.
Keep learning
Connect the dots.
Use this guide as a starting point, then compare it with the water you're fishing, the tackle you're using, and your own observations. Good fishing knowledge grows through real practice.