Interested in making a custom midi controller I just had a few questions from anyone with experience:

1) Where do I buy parts? (knobs, buttons, faders, etc.)

2) Where do I get the central part that would be the core?
- are their different types for different uses?

3) Once I setup parts and solder to the central core how hard is it to set-up with computer?
- is there extra software I need to download to get it working?

4) what types of casing do people use often?
- wood, metal, fiber-glass?

Thank you any information would help and be greatly appreciated