I personally started by downloading some sources, I'd recommend the Oldkoscape server. It's fully customizable. http://www.trap17.com/forums/Runesca...-1-t48427.html
is where I learn how to add in things like commands and teleports - very useful page.
Anyway, you need to get a source (oldkoscape ftw), I personally like the 2005 Rs one cause that's what I grew up with. Clients are just odd. So you DL the source then you make sure you have the JAVA things like JDK and JRE. Then you edit the client.java page in the source folder. The .compile button is what you press when you've done editing. Any more questions I can probably answer, just PM me.
is also a very good page with lots of coding helpz.