Canon EOS R3 Advanced User's Manual page 276

3.
Set the shooting interval and number of shots.
Select an option to set (hours : minutes : seconds / number of shots).
Press <
Set the desired number, then press <
Interval
Can be set in a range of [00:00:01]–[99:59:59].
No. of shots
Can be set in a range of [01]–[99]. To keep the interval timer on
indefinitely until you stop it, set [00].
4.
Select [OK].
The interval timer settings will be displayed on the menu screen.
(1) Interval
(2) Number of shots
> to display [ ].
276
>. (Returns to [ ].)