For those who are very new to disaster preparedness, it is all a matter of getting and storing things for a disaster and when a disaster hits, you use them.
Unfortunately it is not as nice and simple as that. Most of your neighbors are not going to be prepared at all for a disaster. They will get to the grocery to find all the shelves empty and crowds of people fighting over a few packages of food at the cash registers. They probably won't even have any lights except for birthday candles that will be gone shortly.
If your hungry neighbors get home and smell cooking food odors coming out of your home and see lights in your windows, they will want light and food too. If your whole neighborhood is in the same boat except your home, guess what? You could be in deep doo doo.
You may have enough food to last you for a month. How far would that last for your whole neighborhood? Some people do invite everyone in and share what they have until it runs out and then they all starve together.
Maybe you want to do that. If you don't, you might want to plan for being able to hold onto what you have stored. If you want 30 days of light for your home instead of 1 day for the whole neighborhood, you will probably need to hide your light under a bushel.
You will need to cover your windows and you will need to do it very well. One little beam of light could do you in. Pick whatever way you want to black out your windows for a disaster, but make sure it is thorough and won't leak light.
Blackout curtains are an option, but can be pricey. If you want to make your own window blackout covers, you would probably do well to do it ahead of time, and have them ready for when they are needed.
Make something that looks somewhat normal. This could be fabric coverings, reflective ones, paint or plain or colored paper. You can use cardboard or plywood and paint or cover it.
If your windows are small enough you can store them against the wall in the back of your closet. If your windows are too big to do that with your window covers, you may have to make them so they will fold up for storage or you can assemble them quickly when needed. If you are an Alaskan, this is all easy. Just about everybody needs light blockers when the stops setting for most of the day and night. You can just leave your light blockers up all the time.
It is safer to check for light leaks ahead of time. The best is when they are in place on your windows. That way you can be certain they will work.
Even better is having neighbors who are prepared for disasters so it does not matter whether they see your lights or not. There is only so much you can do that way though.
I have already posted about deciding to share your preparedness items or not, and if so, with whom, and how much. You do need to think about this.