Nikon D3300 Reference Manual page 133

4
Close the shutter.
Repeat the operation performed in Step 3 (shooting ends
automatically if the button is not pressed after 30 minutes).
A
ML-L3 Remote Controls
If you will be using an ML-L3 remote control, select one of the
following remote control modes as described on page 97: "
(Delayed remote (ML-L3)) or # (Quick-response remote (ML-L3)).
Note that if you are using an ML-L3 remote control, pictures will be
taken in "Time" mode even when "Bulb"/A is selected for shutter
speed.
P, S, A, and M Modes 113