Here is a picture with the shower door open. The strip slides into a channel on the door bottom. The dealer anchored this new strip with the screw at left.
Here, the shower door is closed and we're looking at the bottom of the strip through the gap at the bottom of the door. This replacement strip has just the tiniest gap there on the right. The old strip was too short widthwise by more than an inch and was a little shorter vertically.