2. Remove the existing battery by cutting the wires. Remember the clock is ticking as soon as you cut the first wire!

 

 

3. Turn the board around where it's "solder-side up" and use the solder wick to suck away as much solder from the solder pads as possible. Hold the remains of the battery leg with the tweezers, touch the soldering iron to the solder and gently lift up the leg. Use the desoldering braid to clean up all excess solder. Use the desoldering pump if necessary to open the terminal holes.

 

4. The terminals of the Keystone battery holder are a bit wider than the existing holes so the existing holes have to be expanded slightly. Use the 1.5 mm drill bit to slowly and gently widen the holes. This must be done from the "solder side" of the PCB to avoid destroying the solder pad.

 

5. Insert the new battery holder, making sure you align it with the correct polarity. Solder the terminals.