Canon EOS 7D Mark II (G) Instruction Manual page 276

Using Wireless FlashN
Setting [E-TTL II meter.] to [Evaluative] is recommended.
Wireless MULTI flash shooting is not possible.
276
Set [Flash mode] to [E-TTL II].
4
Set [Wireless func.] to [0].
5
Set [Channel].
6
Set the channel (1-4) to the same one
as the slave unit.
Set [Firing group] to [1All].
7
The slave unit may be set to any firing
group (A, B, or C).
Fire a test flash.
8
Check that the slave unit is ready to
fire, then while the [Built-in flash
settings] screen is displayed, press
the <B> button.
The slave unit will fire.
Take the picture.
9
Set the camera and take the picture
in the same way as with normal flash
shooting.
To terminate wireless flash shooting,
set [Wireless func.] to [Disable].