Well I guess it depends on what you want to do/are interested in doing. There's a lot of different type of modding you can do for JKA. Are you more interested in modelling, skinning, coding, mapping, scripting, or something else? Since it sounds like you're most interested in making inventory, you probably want to do some coding. eezstreet has a good starting tutorial here: http://jkhub.org/tutorials/article/145-compiling-openjk-win32-must-read-for-new-coders/ I suggest you first get openjk to compile then play around with the code and just try and change a few things. eg: projectile speeds, or something similarly easy Then when you feel you have a bit of experience, go hope on the jacoders irc channel and start asking some questions.