Blinds, Shades and Shutters - New Verticals difficult to slide

I hung two sets of verticals yesterday (standard Home Depot off the shelf 'Grab N-Go'. One set works fine. You have to force the other set in the track to unstack. Stacking is a little easier. The
vertical are open so I'm doing it right. The directions say "on patio door blinds with left hand stack, slide plastic strip out of headrail and slide it back in the other side". I don't know what the are referring to and there is no picture or diagram only the sentence I quoted. Anyone have any suggestions?

Hi!

thanks for your question! I'm very sorry that no one ever was able to answer you. i'm sure, by now, you've gotten it figured out. as i don't personally have an answer for you, my first thought was for you to just call Home Depot and ask them. did you get your problem resolved?

not to make excuses, but there wasn't a Moderator in this forum til recently and, therefore, every now & then, questions went unanswered.

please let us know, for future reference and for the benefit of other members who may encounter the same problem, what you found out!

thanks again! :)