Amongst the easiest of steps. Turn the laptop upside-down, with its lid on the work surface, with the battery facing you.

First, push the left latch from the right to the left. You can let go, as this latch holds its position, unlike the next one.

Then, push the right latch to the right. This latch has a spring, so keep it held.

Next, with the other hand, pull the battery out and back towards you.