Sharon,
You don't need any other software than that which is downloaded to your
computer when you enter the chatroom for the first time.  I also have a set
of headphones with a microphone.  You just plug them into the jacks on the
back of the computer. On my computer, as you face the computer from the side
closest to you, reach behind the computer and you will find the place where
you speakers are plugged in.  That is your sound card.  On it, you will find
three other places to plug in a jack. On my computer the next one beside the
speaker plug is the one for the microphone and I believe the next one is for
the headphones.  The thing to do is try one of the plugs in the headphone
jack first.  If you hear the computer in the headphones, then you know you
have the right wire plugged in the right hole for the headphones.  Then plug
the other one in the jack, probably, between the speaker wire and the
headphone jack.
I hope this will be of help to you.

Ned