HELP buddy buckets need install new cover help my guy is lost

[master 1969 c10]

Hi I bought a set of buddy buckets new covers foam from the pick-m-ups ( frank ham)
I took old covers off a cleaned painted everything don't have old covers anymore my installer is having problems on the back part of seat he says there is no way to hog ring the on. these seats can fold forwards. frank was no help at all. The back cover looks like it just slips over the frame and there is no way to hog ring them. Please can someone help with pictures or talk to my guy. maybe I was sent wrong covers I don't no I have called 2 other people that sells the pre made covers for the buddy buckets no help. my number is 614-218-6977 doug or u call call my installer been doing this for 40 years his name is john 269-986-4800 or 269-968-4800. I Live in lower Michigan if someone out there can help install. thanks Doug