I’ve just made these blinds myself they were a fucking annoyance, but basically the blind fabric is a loop. When it’s hanging up, just slip the metal bar in the loop, it’s purpose is to weigh down the blind so the fabric lays flat

I’d like to know this too please

Should just be a bar that slides on in

Stupidly complicated design destined for the bin. No idea how the bar attaches apart from a stupid bit of nylon