Read this and any further questions you have can then be asked. This thread covers an LED, but in order to do the LED you have to do the switch first. So, this thread covers the switch. Once you have successfully done that mod you can move on to the pot question
This. You can drill a hole in the case and stick a switch in it. Drill another and stick a pot in it. Since you're not looking for true bypass, then the extra pot and extra switch will not be used for that.
Now, I can assume you want to add this pot to control the Q of the effect, and maybe use the switch to bypass that knob, or I can assume you want to use the switch to change between different cap and resistor values, or maybe you've got 2 different inductors and you want to switch between them with the switch and/or blend the two with the pot or maybe do some mod you heard about on a completely different forum somewhere that is only known on that forum. I don't know what you want to do with the pot and switch so I cannot tell you how to wire it up.
Or are you putting the board from the pedal inside your guitar?