It's so easy it would make your head spin.
You'll have to take the control panel down, then the glass, bezel and maybe front wood frame off of cab to get to the bare monitor. First, the monitor is held in by bolts on the front of the machine. Usually 6 (3 on top, 3 bottom). Take them off and it will still sit on the wood frame. In the back, the things that run the monitor are the power cord, and the video signal. Also, there will usually be a ground wire on there (green wire).. you have to take that off, too. So, unplug all of that and remove the monitor from the front (where you took the bolts out). Just be damn sure you don't touch anything in the back of the monitor, you can get shocked off your ass, if not killed. Yank it out, set it where you want to... replace the other one in the reverse manner.
When hooking the video up, be aware that there will be a red wire, a green wire, and a blue wire (this is the actual video signal). There should also be a black and white wire (but sometimes, these are different). One is vert hold, one is ground. The cables used to plug into one monitor aren't always (and usually seldom) are the same. I usually just splice the wires together, but I do things the wrong way. lol
If you need help, give us pics. It's easy, don't worry.