Can someone explain this to me?

[Landberg]

Hi! My xpan is a bit of in the rf adjustment, i found this guide but i can't understand it. Can some one explain this?

http://photo.net/leica-rangefinders-forum/008zw6

 

[kbg32]

I think it would be better to have a camera repairman do it. Huw is a very experienced technician.