Use a narrow screwdriver to pry
the keys off the keyboard. In most cases they will just pop right off.
Look at the backside of the keys. If the mounting tabs stick out past the body of the key, then you need to trim them so that you can mount the magnets flush with the backside. You can either cut the tabs with wire cutters or just break them off with needlenose pliers.
My name is Jason Poel Smith. I have an undergraduate degree in Engineering that is 50% Mechanical Engineering and 50% Electrical Engineering. I have worked in a variety of industries from hydraulic aerial lifts to aircraft tooling. I currently spend most of my time chasing around my new baby. In my spare time I make the how-to series "DIY Hacks and How Tos."