HP EliteBook 840 G6 Maintenance And Service Manual page 60

3. Rotate the top of the battery upward (1), and then lift the battery out of the computer (2).
IMPORTANT:
into the computer (3), and then rotate the battery into place
Reverse the removal procedures to install the battery.
50 Chapter 6 Removal and replacement procedures for authorized service provider parts
When installing the battery, insert the tabs on the bottom of battery into the clips built