Garmin G3X Pilot's Manual page 431

1) After the data has been copied to the SD Card, insert the SD card in the SD
card slot of the display.
2) Power on the display. The Update Databases Page is displayed. A green
checkbox indicates that the database already installed on the G3X is up
to date. An empty checkbox indicates that the database on the SD card is
more current and should be installed.
3) With 'Update All' highlighted, press the ENT Key. The database status is
updated.
Or:
Move the FMS Joystick to highlight a single database to update, and press
the ENT Key. The database status is updated.
190-01115-00 Rev. K
Update Databases Page
Update Databases Page
Garmin G3X Pilot's Guide
Appendix C
409