Here is a more complete instructions for looking at CMaps online
CMap Instructions for Exploring C Maps online
Go to website Click below
Search Charts C-MapsFill in the following Boxes
Location; Put in either where you live or what lake you want to look at.
Chart Plotter Brand; When you select your Brand and Model It gives you the list of Maps that work on Your Unit (No More Guessing)
Chart Plotter ModelChart Product; Most People want to look at Discovery or Reveal. If you fish crappie or Bass Look at Reveal, If you fish all over the Us and Canada then Pick Discovery
Coverage; Put in Lakes Regional
After all the boxes are enters click on Search
A List of Maps will come up on the left side of the US Map Click on the one you want to explore. The boundary of that map will be displayed on the US Map
Next Go to the Round Button with 4 arrows upper right hand corner and click on That.
This Expands the map to full Screen and Displays an ICON call layers
Click on Layers and Turn on HRB High Res Bathy
Zoom in on the Map Boundary and Find your Lake zoom in till you see the contours
Maybe one of the Forum Gurus could post this for more people to use