RPGM How do you mod a RPGMV game?

[F22232425]

I am trying to mod a RPGMV game which is deployed with encrypted images and audio files.
I want to extract its content to my new project folder in order to modify the game content.

Here are my steps but failed at loading when testing:
I first use RPG-Maker-MV-Decrypter to decrypt rpgmv files
and then put them inside new project folder with everything else of that game.
When I test it inside RPG maker MV, it says "Failed to load iconset.png"

 

[redknight00]

Don't playtest, copy and paste the changed files to the base game folder, there are differences in the packages used that you won't get when playing directly from RPGM editor.

Plus the System.js is still probably set to encrypted, that's why it's not reading the png file.