It contains a wide array of utilities and abstracted UI classes that can increase your producitivty.
Import the library into your project source, or compile the SWC file and include that instead.
To generate documentation, compile the swc or run the unit tests, create a file named user.properties and define the path to the Flex SDK. For example:
FLEX_HOME = /Users/Matt/SDK/Flex/4.1
Build/compile the SWC
ant build
Run unit tests:
ant test
Create documentation:
ant docs