I'm assuming I have 100 slots on my CODE 50 for whatever presets I choose. How do I specify which numbered slot I wish to update or change with any of the presets on MyMarshall.com. Not sure if this question makes sense or if I even worded it correctly.
Yes, Robert, this question definitely makes sense... :-)
Supposed that your amp is correctly connected to PC, and your broser supports MIDI, you can enter the PRESET section on this page, choose desired preset and click the amp icon. Downloaded preset replaces currently active slot of your CODE. Then you are able to check if the sound meets your expectations, you can modify the settins and - if everything is OK - don't forget to SAVE the preset. If you're not satisfied - don't SAVE, just switch to another preset and all changes are gone.