How do you install a 12" VPI armboard for 12" Unipivot on a VPI Classic 3 - Thanks :-)

I'm considering upgrading my VPI Classic 3 turntable's metal 10" JMW UniPivot tonearm to a 12" 3D printed UniPivot tonearm.   I've some technical know how but want to double check how to install the new VPI armboard.  Any step-by-step guidance here and / or where to look for advice online is very much appreciated.  Thank you!  :-)