what you will need is microsoft visual studio 10 and install it, once it is installed goto your rathena server folder and find rAthena-10.sln. Double click on it and a box will pop up select microsoft visual studio 10 and then it will open, once open it will show you char, login and map either txt or sql. Hold ctrl and select the 3 that you need either all txt or sql. Once all 3 is selected right click on one of them and hit clean and then build and there you go. If it says 3 success then you have compiled your server.