how to use the 3 way chat please?

We have purchased a 8200a Digital Cordless Phone with Answering machine. Both of our children live interstate and when they ring us or we ring them, it would be nice if both my husband I can listen and talk to them at one time. I have read the instruction book, but are uncertain what to do. Thanks for your patience and time.

Janette Cleaver
February 2011