Really Simple if its an updated source code
Change the Defaultcharclass and comment in Glogic.rcc
Load and save crow,item,skill files with editors
Replace the old game.exe with the compiled one
then their you go add more items if u feel like modify the items , skills , add some mobs if u want
all depends on u change gold rate exp rate at defaultcharclass depends on what kind of client u want
low rate, midrate, highrate, people these days want mid-highrate or i like to call balance server