Start by drawing what you understand and believe will be a viable/workable switch wiring diagram.
Scan or photograph your wiring diagram and post the image here via imgur (
www.imgur.com).
Then list your questions and concerns including references etc. regarding your planned switch design.
A schematic will be very helpful in understanding the requirements and how the switch will be built.
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Or, go online and search "Guitar Sliding switch schematic 9v 12vdc".
I found quite a number of possibilities: for example:
https://www.pinterest.com/pin/unique-import-5-way-switch-wiring-diagram--950048483863271709/
Some possibilities seem quite involved and other possibilities seemed over-simplified.
Do your own search and select two or three links that are similar to your switch requirements.
Post accordingly.