Nikon D3300 - Manual (Page 128)

108 P, S, A, and M Modes
Mode M (Manual)
In manual mode, you control both shutter speed and aperture.
Shutter speeds of “Bulb” and “Time” are available for long time-
exposures of moving lights, the stars, night scenery, or fireworks
(
0 110).
1
Rotate the mode dial to M.
Mode dial