1. Download and unzip the file
2. Open up DTW and open the ISO you want to change (whether it be 20xx or a melee copy)
3. Scroll down to the stage/character list, and then highlight the stage/character you're looking to replace by clicking once on it.
4. Click 'Import' on the right side of the window.
5. Find the file you downloaded in step #1 and open it
6. The file is replaced, now just do Ctrl+S or go to the top left and select 'File>Save (CTRL-S)'
7. Now just load up the game and the texture should show up ヽ ╭ ° ͜ʖ͡°╮ﾉ