You will need to put your SIM into the SIMtrace hardware, connect one of the four flex cables to the SIMtrace hardware, put the other side into the SIM socket of your phone. Use USB to connect the SIMtrace hardware to the PC. On your PC you should be able to see the USB device now.

SIMtrace being connected

$ ./simtrace simtrace - GSM SIM and smartcard tracing (C) 2010 by Harald Welte <laforge@gnumonks.org> Launching the simtrace will try to find the SIMtrace hardware and then try to claim the USB device. The application will send the received data encapsulated in the GSMTAP format on localhost and the IANA assigned GSMTAP port.

The wireshark application will start a GUI and given the right permissions you should be able listen to the localhost interface and filter for the GSMTAP port on 4729. You should be able to see the decoded messages like in the figure below.

SIMtrace sending data