1970 Challenger wiper blade assembly

i am looking for pictures of the wiper blades installed. i am confused as to the separate arm / linkage on one of the assemblies and how it attaches??
i have owned car for 25plus years and have never had wipers working on them (AZ - it's a dry heat).
Car show and cruise was a downpour. i need to be better prepared.
thank you.

The driver's side arm has the extra rod that attaches to a little pin near the base of the wiper arm with a little clip. Someone was reproducing the clip, but I'm not sure who. I think I saw them on eBay.

http://www.ebay.com/itm/Mopar-E-Body-1970-74-Windshield-Wiper-Arm-Set-Cuda-Challenger-W-Clip-/271941965422?hash=item3f5101166e:g:Mx8AAOSw9N1Vtq2w&vxp=mtr

4th picture shows the arm w/clip on it.