If it's a side scan unit, it takes a bit of time to get the hang of it. I do like to show the water column for those fish I pass directly over, they show up better in the dark column rather than the clean bottom view. That would be under the SI enhance menu.

I'm a believer in the recordings for learning. I like roughly 10 minute segments or so; others claim that the longer ones can take a long time to load in something like Humviewer. Don't be shy about changing color pallets, sensitivity, contrast, etc. when playing back the recordings. Even changing the back lighting level under the power button can change how the display looks to your eyes. You may find that what looks good at home is not the same as what you like while on the water but at least you'll have some sort of baseline comparison to work from.

I fish small waters myself, less than 100 acres is my rule. 95% of my fishing is in less than 20' of water. I like to keep the side view at less than 50' since my waters are small and it doesn't take too long to cover most of it. Easier to see things when you don't compress a long view in to a short space.