Honestly, I Looked it up on YouTube...
I wouldn’t unscrew the one that just has a half link and one screw on each side...
what I did is unscrew both screws on the side of the end link, put those tiny screws In a safe place, and then you basically pull out the other End-piece on side of the link. There are two long pins attached to that end-side-piece that go through all the middle link pieces and that you ultimately screw those tiny screws into..
Repeat that process on the next link up and then just take two of the middle pieces and put them in the middle and then take the end side piece with two Long pins, slide it back through the two holes, place the other end piece that holds the tiny screws back on top, Screw in the two tiny screws and there you go.
if you need another link, take it out of the other side.
point is, for one link you’ll unscrew four screws. Two for each side piece.
you’ll pull out 2 side pieces and you’ll have enough middle pieces to thread onto the long pins and then screw in end side piece at the top!
the pic below shows what you’ll have left over... 5 middle pieces. One end piece with 2 long pins attached. 1 side-end-piece that holds the tiny screws...