There is a mirror image plastic piece on the other side of the glass and they are held together with a metal pin between the two in a pair. There's a pair at the top and bottom of the glass. What is tight is the plastic pieces, plus the flocked plastic seal. You have to install the plastic glides and the seal on the glass and then feed them up the channel from the bottom and then install the whole thing in the door. At the very bottom is a near 90 degree bracket. This is definitely a "two sets of hands" project to get them back in. Unless your glass sweeps at the top of the door are new. This is the time to install new ones because it's hard to get the glass in or out with the sweeps in place - pull the old ones, install the glass, adjust he down stops so you can get the glass below the sill, then put the new sweeps in place...
