To replace a pair of heeltips you need a pair of pliers and a hammer. If you don't have one, ask a cute neighbor!
Replacing your tips is quite easy. Just follow the instructions below:
With your pliers, try and get ahold of the old heeltip and pull it out.
Move left and right, if it doesn't come out right away. Eventually the tip will come out.
Simply replace the old heel tip with the new one and use a hammer to drive it into the heel of your shoe.
If you don't have a hammer you can knock the shoe against a hard surface (but don't damage anything, of course).