Basic MIDI setup using only the Soundcard Port
Keyboard MIDI OUT--------->Computer MIDI IN (essential)
Computer MIDI OUT--------->Keyboard MIDI IN (if you are only using your soundcard's "onboard" synth this connection is not required. If you want the computer to play your keyboard, or if you want to connect a 2nd module it is required)
Keyboard MIDI THRU ------->Keyboard or Module #2 MIDI IN (optional)
Keyboard or Module #2 MIDI THRU -----> Keyboard or Module #3 MIDI IN (optional