While we typically do not assist with homework, showing how to use the command line to run Wireshark is okay in this case. As for interpreting the captured traffic, that's another story.
Add the
-k option to start the capture.
eg:
wireshark.exe -i 192.168.1.2 -k
I suggest you take a look at the Wireshark documentation for details on running Wireshark from the command line for more information:
http://www.wireshark.org/docs/wsug_h...ustCommandLine