Trying to power RAMPS - No Electronics Experience (2 replies)

Hi all, I am trying to figure out how to power my RAMPS for a senior design project. I am a mechanical engineer so I know only a little about electronics, i.e. i know what the diodes and pins are and some other basics. But going through the forums to figure out how to make it work, I keep running into the problem of I have know idea what those words mean. Basically I have an arduino MEGA with what I assume is its cylindrical power input for a wall jack, and its USB printer looking jack to hook up to a computer. On the RAMPS I know that there is a 5 amp input and a 11 amp input that is for heating and they are located at the bottom left of the board. I don't need heating for my project, just motor control.
So firstly what I originally thought was that the arduino had to be powered separately from RAMPS but some of the post indicated that the ramps power supply could power the arduino. Is this correct or am i misinterpreting things?
Secondly, some people were mentioning that RAMPS could be powered via USB. I know this is a stupid question, but there is no USB port that I can see on the RAMPS and from what I've read the arduino doesn't have enough juice to power everything on RAMPS so how is this possible?
Thirdly, if I just want to hook up RAMPS to power 3-5 motors, do I just hook up 12 V to the bottom side 5 A thing or do I have to attach something to 5 V and other pins located next to the reset button.
Thanks in advance for any help. If these questions are just too noob for this forum, let me know and I'll go bug some other people :D