Nitrous plumbing A1A...??..

The first things that I've ever bought and had more questions than answers when I got them... First and foremost why didn't they put little screws in there so you can mount them? Why didn't they at least give a little piece of paper telling you what size the screews might be? Is there no negative or no positive wire? Just connect one to one and one to the other?? The inlet is in the back and the outlet is in the front? Pretty much forcing it to mount it backwards or sideways? Manufacturers I would think you would want there label to stick out? of course the picture on line shows in the side and out the other side..
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