Nikon D780 DSLR Camera (Body Only) - Manual (Page 529)

483 Remote Flash Photography
D Listing Remote Flash Units
To view the flash units currently controlled using radio AWL, select [ Flash
control ] > [ Radio remote flash info ] in the photo shooting menu. The
identifier (remote flash unit name) for each unit can be changed using
flash unit controls.
D Reconnecting
As long as the channel, link mode, and other settings remain the same,
the WR-R10 will automatically connect to previously paired flash units
when you select remote mode and Steps 3–5 can be omitted. The flash
unit
LINK lamp lights green when a connection is established.
1 Connected flash unit
2 Group
3 Flash-ready indicator