That stuff is well out of date. You can get rolls of plastic draught excluder, there's all sorts available, try eBay.
I've always found that a thick pair of curtains that fall past the windowsill help.
Indeed, I did look before posting this note. Regrettably none enlightened me. I'm guessing it folds into a v shape & fits into the angle furthest from me, where the edge of the door fits, but had hoped to be clearer. Don't want to fit it incorrectly so I can't open/close the door.