Cameras need light, there isn't much at night.

Long Exposure.
You need something to rest the camera on something, ideally a tripod, so it doesn't move, then set your shutter speed to a couple of seconds or more depending on how dark it is.
You could also increase the ISO as that will increase the brightness, but you'll get more noise (speckles) in your pictures.
If you can't see where you're walking it's probably a bit late.