can anyone help me make my linn valhalla power supply dual speed?

Hello - just for fun I got a linn valhalla board. I know its probably wasnt a wise idea but i like playing. It working fine but i am going a complete service and re cap on it.

I read this post https://www.diyaudio.com/community/threads/two-speed-valhalla.97740/

and I can see somoene uses a DPDT relay to switch out the existing crystal with a higher frequency and at the same time change the phase shift cap.

Can anyone help me make this easy to understand so I can have a go doing it myself?

Thanks
Chris