It's not the best idea to do your own bangs, but if you're really short on money and can't afford to go to a salon to get it done this is the safest way to do it. While your hair is wet, make two decently sized sections on either side of your head and bring them to the front. Take the remaining hair that isn't in your two sections and tie it back with a pony tail. Then take the two separated sections and brush them forwards so that they're in front of your face and you don't have a part on the top of your head. Figure out how thick you want your bangs to be, and take just about that amount of thickness of bangs and start snipping. (It's a good idea to go thin at first, you can always cut more.) Don't cut too short at first... Start long, you can always cut more.
The bangs might not stay in the front so well at first, and if that happens all you have to do is train them for about twenty minutes a day and maybe while you're sleeping. To do this just take two bobbypins and clip them on either side of your bangs facing inward. Good luck!
First, you should dampen your hair and comb down the amount of hair for the required thickness of your bangs. Tuck the rest of your hair behind your ears, or pin it back. Gather the hair in one hand and twist it a few times. Take the scissors and snip the length off roughly at the length at the bridge of the nose - that will give you a little extra length to trim back if needed, but you'll see that the sides of the bangs are just a little longer than the centre, so it frames your face nicely.