Tutorial
The Legend Defines the symbols currently displayed on the map.
shows how the layers A group of the same type of features that you can view on a map, such
as parcels, water mains or street names. The data for each layer resides
in a database table, where each individual feature of the layer is represented
by a row, and the data connected with the feature (i.e. house number,
APN, etc.) is stored in fields (columns) in the table.
are displayed in the map.
Note: If aerial photographs or other graphical layers are turned on, you find Color information (such as RGB or gray scale samples) in the legend as well
Try it out!
Click
the Layers
tab and check a couple of layers. Try to select large features A piece of information that can be displayed on the map such as a parcel
number,fire hydrant, or aerial photograph. Each individual feature is
represented by a row in a query table. (See "table")
that have many instances, so they will be easy to find on the map.
Click Advanced
Toolbar 
on the Main Toolbar.
Click the Legend
tool in the Advanced Toolbar
to display the legend.
Find the features in the legend on the map.