Gently pop the old or new key back into its place, ensuring that it is tight and secure.

Make sure that the bar that belongs to some of the keys has not popped out of place. If so pop back into place in the sockets it has underneath.

For the keys with a bar, slide one side into the bar and then use the metal spudger to pop the other side into place and test the keys to see if it still sticks.

Use the picture from the beginning if necessary to make sure all the keys are in the right place.