Open the frameless shower's door.
Pull the gasket apart by the edges separating the gasket’s two sides. The gasket is very snug and the sides try folding back together, which helps the gasket keep from sliding off the shower door.
Slide the door gasket onto the door’s bottom, starting at one end. Do not use a lubricant to help slide the gasket onto the door as the lubricant may cause the gasket to slip off the door.
Pull the gasket by hand up onto the bottom of the door until it is secure and flush with the door’s bottom. The door is smooth, so the gasket’s snugness keeps it in place on the door.
Continue sliding the gasket up onto the door’s bottom along the entire length. Since the gasket fits tightly against the glass, it stays in place once you release your hold on it.
Close the door, ensuring that it shuts properly with the gasket in place.