I admire you just for trying.

It's much easier to have a camera with full manual control and full information LCD. It's always better to try something else than keep wishing.

I suppose your camera doesn't have manual exposure control(aperture, shutter speed).

The next best thing you can try is to

* press the shutter button half way while aiming it to something else in the dark and in the about the same distance to the light pattern you are trying to show. That'll lock the exposure and focus, you can't separately lock them. Then keep holding the shutter button, turn your camera toward the light pattern and give it a full press.

* Check the shot you just took. If it is over powering bright, light that "something else" you used to lock the exposure little brighter(but not as bright as the light pattern) then repeat the step above.

If this works, you'll know by the first shot you take. Repeat it in different amount of light, you'll get the hang of it.

Your camera may have the control that you are not aware of. If you can tell me the make and the model of the camera, it's eaiser to find out.