I love Heroes IV! It's one of my favorite games from my childhood.
Now, when I'm older, I revisited the game and I found it very interesting, but there are few things that I would like to add/change and as I saw there are many mods available and I'm happy that many players already know perfectly well how to modify the game files. Unfortunately , I'm not one of them so I want to ask you for help.
I want to :
1.Modify creature's damage and price
2.Add/replace creatures as available in the towns.
3.Add an entirely new spell (dimension door) .
Can you help me with my quest to modify the game

I already installed "H4ResourceEditor" and "TextEdit" , but I'm not really sure how to use them and do I need an additional software for my mod?
I have some programming experience, but I never tried to mod a game.
Thank you for your time !