[Help Building Laser] - Laser Noob Needs Help Please ;)

So i've had this laser for quite a while and the button broke. I've been wanted to try to build my own laser for a bit now but have no experience. I couldn't find a video about this because I didn't know what to do since I dont have the spring that was on it and the button is broken so I didnt know how to get around that but i know you can probably make it without a button. I wanted to use the button on the flashlight if that would be possible but I would be happy if I had to take the batterys out every time since it is my first time trying to build a laser. I also dont care if you cant explain or it is not possible to put the laser in this flashlight because I think it might be a bit too small but if I can get it to where it can go used just outside of anything without a casing, Im sure I can find one thats cool if i can get the laser running.

Any help would be much appreciated.

Need Help Building 5mW laser out of Ebay Laser - YouTube
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