The weatherstripping on a prehung steel or fiberglass door typically consists of four components. First there are the are the side and head jamb bulb seals. They are like the one you listed the link for. They are often proprietary, and some are clearly marked. Therma-tru brand, for example, molds their name into their bulb seals. If you can find a name on the hinges, bulb seals or other parts, you might be able to find a direct replacement. I have also sucessfully used gewneric ones that fit well. When you do replace them, it's a simple matter of pulling the old piece out of the groove in the jamb and pushing a new one back in. Most need to be trimmed to fit, so cut them a bit long, like a 1/4" or so, on the long legs, so they fit tight. Next there is the sweep on the bottom of the door. This is typically a flat rubber piece with a few short rubber fingers that hang down, making a good seal. The sweep is commonly glued and stapled to the bottom of the door, so you need remove the door, and place it on saw horses to remove and replace that piece. There are also small foam pads that are often placed in the corners of the frame and seal the corners of the bulb strip. These are self-stick and about 1-1/2"X 3". They come with the door and are frequently missing, or even tossed out by whoever is installing the door. If used properly they can make a big difference. Finally, there may be an adjustable sill, that can be raised or lowered, to allow the sill to meet the sweep tightly, and keep air from leaking under the door. If any one of these four components is missing, torn, worn, or mis-adjusted, the door can leak a LOT of air.
