Nikon D780 DSLR Camera (Body Only) - Manual (Page 263)

217 Shooting Settings
2
Select a preset.
Press the Q / g ( U ) button and rotate the sub-command
dial until the desired white balance preset (d-1 to d-6) is
displayed.
3
Select direct measurement
mode.
Release the Q / g ( U ) button briefly
and then press the button until the
L icon in the monitor starts to flash.