What's wrong with it?

Door gaskets are generally attached in one of two ways: They're either pressed in, or they're attached with screws (and these screws are usually hex-headed--1/4 inch).

Gently lift an inside edge of the existing gasket. That's the edge that faces the inside area of the door; not the outer perimeter. If there are screws, they will be spaced fairly evenly, about every foot or so along the length of the seal.

If there are screws, pay close attention to how they attach the seal to the door. Remove only a few at a time. As you remove the screws, also remove that part of the seal and start working the new one in place of the old one.

Continue on around the door, until the old seal is completely off and the new one on.

You'll notice wrinkles and krinkles in the new seal. They'll have to be flattened out until the door evenly seals against the refrigerator body. A full seal usually can be accomplished within a day of the new installation. Blowing it with a hair dryer usually helps it to expand fully.

This appears to be very simple; but can be very frustrating. You'll need a lot of patience when doing this replacement, but it is well within your ability to get it done!