How do I replace my power button?

Hi I have a Swift 1 which I need to repair /replace the power button. It does still function, but it takes a lot of thumb pressure and wiggling my thumb up and down the button.

I don't know how the switch actually works, but am guessing that there is a contact which is worn?

Any advice or websites / you tube videos which might help me understand how it works - and the best way to go to get it fixed will be gratefully received!

I know it's an outdated model etc, but I agree with this site about not just chucking electrical stuff away if it can be fixed reasonably cheaply!

Thanks

Jon