I've never used MIDI but I know a little about it.
Google can help you find a list of CC messages and you'll have to check the documentation for your software/virtual/instrument/MIDI instrument to find out which CC messages are supported.
Some CC messages are "continuous" (0 - 127) and some are on/off ( 0 or 127). If you're using a pot, presumably you won't be using it for on/off so you'll need to map it 0-127.
You need to send the message (one byte) plus the intensity/mapped pot value (another byte) but I don't know the details of how to send those messages.