Flagging key concepts is strictly a communications tool and has no other impact on the behavior or scoring of the Personal Study Plan.
Open the My Classes page.
Click Classes › My Classes and find the section you want.
Click the Personal Study Plan tab.
Select the Flag Key Concepts check box.
Expand a chapter with sections that you want to flag by clicking
.Click the flag icon
for a section to change its status.Flag Color
Status

The section is not a key concept.

The section is a key concept.
Click Save.