1. On the underside of the laptop there are 8 screws. Undo them all and lift the back off
  2. Inside, there's 5 screws holding the battery in place. Undo them and flip the battery up and out of the way. You don't need to unplug the battery
  3. On the left side there is a CR2016 battery connected with a JST connector and a red and black braided cable. Unplug and install a suitable replacement. A larger sized battery (e.g. a CR2032) can be used, as long as it outputs 3 volts and fits in the space provided.