need advice on how to make mods for hexen

[jonc2006]

hi im very intrested in making a rpg mod for hexen that will suite to my liking, ive seen the korax mod and while there are lots of good ideas and elements in it, there would be alot of things id change if i could, so i want to learn how to make one of my own for my own personal use, im in no way trying to rip off other peoples ideas im just trying to customize my game. my aim is to make a mod that acts like the level/experience system in hexen II, as well as add things like invetory item limits for each item and as you level up or find like a backpack powerup or something you can gradually hold more of each. i have also seen a second mod that uses rpg elements on jfiles but imo that one is fairly unbalanced and ive tried to contact the author of that mod to try and make him even it out a little cus it feels like cheating towards the end of the game.

so could anyone with experience with this kinda thing point me in the right direction concerning what programs i should get, tutorials etc. im not really intrested in map making, but moreso changes to the gameplay to make hexen more like hexen II. again i have nooooo experience in this field so any advice, programs or whatever would be really useful, i really just dont know where to start so can someone help me out here?if anyone wants to email me instead im at floppo8@hotmail.com