How to use a 12V 20A Universal Regulated Switching Power Supply

I just got my 12V 20A Universal Regulated Switching Power Supply from ebay and I guess I'm in a little over my head now. I searched and searched for resources on the web and in the forums but apparently everyone else somehow just knows how to use these things.
My main question is how on earth am I supposed to hook it up to the wall socket? I assumed it would just plug into the wall, but apparently I have to make my own plug? I guess at some point I'll also have to figure out how to wire the RAMPS board to it, but for now I really just want to power it up so I can make sure it's working.
Can anyone help answer these questions for me? And please don't assume I have "scrap" anything just lying around in my shop. I live in an apartment

You need to use a three core mains cable and a plug. The first three terminals will be labelled something like L N and E (or an earth symbol). They need to be connected to live, neutral and earth in the plug using the correct coloured wires depending where you live. Brown, blue and green / yellow in the UK. I think black and white, green in the US.

The easiest way is to buy a complete mains lead and cut off the equipment end, saving you the hassle of wiring the plug.

It is a good idea to make a cover to cover the connections, especially if you have children or animals, as this type of PSU is intended to be inside equipment, not exposed.

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[www.hydraraptor.blogspot.com]

Thank you for the perfect explanation. I thought I might have actually had a computer cable laying around that I could use, but I looked and I don't. I'm looking at this one on amazon(http://www.amazon.com/gp/product/B000BQMOS4/ref=olp_product_details?ie=UTF8&me=&seller=) but it says 13A. Is that OK even though my supply is 20A?

Yes that will be OK. The output current of the PSU is 20A but that is at 12V so the input current at 120V will be roughly one tenth of that, i.e. 2A.

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[www.hydraraptor.blogspot.com]

Can you help me interpret the rest of these symbols?



My understanding from left to right:
Live, Neutral, Ground, ??, ??, ??, ??, ??, ??, ??

The three marked +V are the 12V output and three marked COM are the 0V return.

+V Adj is a preset potentiometer to tweak the output voltage.

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[www.hydraraptor.blogspot.com]

So I should connect a V+ to the + on the RAMPS board and a COM to the -?

Yes

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[www.hydraraptor.blogspot.com]

thanks everyone. this was quite helpful!