[amsat-bb] Packet Sats. Need help.

Hello all. I have been dabbling a bit with the Packet aboard the ISS. I was able to copy the downlinks for the past few days. BUT...what I don't understand is using Packet Engine Pro and my Athlon, how do I setup to transmit? I can't seem to find any place in the program to enter text, my callsign, etc.

What else do I need to know???

Thanks

John KB2HSH