this is what i did this morning when i was playing with the software:
connect the cable to the OBDII port.
connect to your serial port.
(edit: added line) turn the key to the "ON" position
start the software.
(edit: added line) i selected "no" in the "new ECU" popup
select the port that you are using (on my T40 ThinkPad & USB adapter it's port4)
click on the "Live" tab
select the items that you want to view OR under "Capture" you can "Select all analogue data items" and "Select all digital data items"