1) Step through every single menu option; investigate (via manuals or google search) what each one is for if you do not understand. Sadly, the user manuals are incomplete in this area. Shame on Lowrance for charging premium $$$ without proper documentation in support of the user. (This is a critical review, not a bashing, as I own numerous Lowrance units.)
2) Watch You-tube videos. There are a lot of them. You'll find some channels are better for information than others as you begin watching them.
Amen, go through it. Every single option to learn what it does and read multiple forums to learn more. The manual is now built into the graph in the "files" page, I just don't know if it's the original manual or if it's updated to the new changes.