A couple quick pointers for ya,

1) "Do not" use fish symbol, turn them off, the unit will give you more info with those symbols turned off. Instead of everything just looking like a fish, with symbols off, fish look like slashes, bait appear as a ball or cloud and thermoclines aa a fuzzy line accross the screen.

2) Learn how to do all the adjustments manually, do not use auto-settings, once you getting your unit dialed in, you will get alot more info out of it.

3) I always recommend running dual frequency units on "dual frequency", there will be times when a fish or bait will show up on 1 frequency but not the other, by running on dual you will see more then sticking with 1 frequency over another.

4) I know you said it was mainly for freshwater use but if you do any bottomfishing, switch to 200khz frequency and turn on the bottom lock.

5) See suggestion 2 again.

Good fishing