Connect the XLR or 1/4-inch TRS cables to the Auxiliary Send sockets on the M7CL. These may be located in a labeled group on the rear of the M7CL. It doesn't matter to which you connect -- just make a note of which one it is.
Run the cables to the computer's audio interface and connect them to the input. Connect another cable to the computer interface's output and run it back to the mixer. Connect the cable to the Auxiliary Return socket that corresponds to the Send you used earlier. If you went from Send 3, for example, connect to Return 3.
Launch the VST host application on the computer and load the desired VST effect plug-ins.
Access the main mixer view on the M7CL's touch screen. Each mixer channel has a double strip of digital knobs, colored purple, blue and gray. Press a knob to access the Mix send pop-up. You can then change the destination of the individual send controls to direct them to the numbered Auxiliary sockets that you chose.
Turn the knob to increase the amount of signal from the mixer channel that is sent to the outboard VST processor.