The Chronos Digital Game Clock is a great device for timing chess games and other games, but it took me a while to learn all its features.
Here is a PDF with tips on how to get the Chronos II to use increment or delay in chess games.
Chronos II Tips for Increment and Delay
Here is a PDF that summarizes the basic operations of the clock. It is formatted to be small enough that you can cut it out and tape it to the bottom of the clock.