Nikon D3300 User Manual page 278

To choose a value for exposure compensation, keep the E (N)
button pressed and rotate the command dial until the desired
value is selected in the viewfinder or information display. Normal
exposure can be restored by setting exposure compensation to
±0 (adjustments to exposure compensation in % and I modes
will be reset when another mode is selected). Exposure
compensation is not reset when the camera is turned off.
E (N) button
A
The Information Display
Exposure compensation options can also be
accessed from the information display (0 9).
A
Mode M
In mode M, exposure compensation affects only the exposure
indicator.
A
Using a Flash
When a flash is used, exposure compensation affects both background
exposure and flash level.
+
Command dial
–0.3 EV
Information display
+2 EV
P, S, A, and M Modes 119