Do you mean a bot like Scion bot or a script? A script is pretty easy to make. Id suggest SCAR http://www.villavu.com
because it uses color, so it doesnt hack the client or anything like that, making it undetectable. It is also very easy to learn.
A Bot like Scion Bot though would be a little bit harder. Im not really sure how it works, but you need the main interface and a whole bunch of side programs and files to compile the scripts and stuff. Since im not really sure how to do this, could somebody tell me?