There will be a light yellow rubber stopper that is holding the antenna in place.

With your tweezers, gently tug on the stopper to make it come out, or at least come loose.

If the stopper does not completely come out, use the round top of the antenna to push down on it.

You can do this simply by pulling the antenna as close to the back casing as possible, and then pushing down on it until the rubber stopper comes out completely.

After it has come out, it can either be taken off from the antenna and set aside, or it can be kept on.