1:Download all the folders in the link
2: in the game file folders you should find: Graphics-> Characters -> a bunch of folders called “Bike” “clothes” “Clothes_back” “clothes_front” “Run” Those 5 folders are the ones you are interested in. The folders in the download mostly match (“walk”=“clothes” btw)
((on mac to access these folders you have to right click the insurgence program, and hit "show package contents. from there the steps are: drive_c ->Program files->pokemon insurgence [version] Mac-> [all the steps mentioned before]))
(((ALSO if you are on mac, I’d recommend organizing the files by kind, otherwise the folders are scattered between the .png files)
3: Chose the hair color you want, they are numbered in each of the folders to match the order in the example picture (purple=1,blonde=2, red=5, dark blue=12, etc.)
4:pick an old hair file to replace with with the new file, and find the number it is called in one of the folders. (for example, the female purple hair is “hair1”) ((also anything ending with an “a”, as well as hair12-17 are not yet usable in the game as far as I know, so do not mess with them))
5: Rename the hair color files in every folder of the color you chose in step 3, to the name of the file they will be replacing that you chose in step 4.
6: move/copy the new files into their respective folders in the game files, it will likely warn you that there is already a file existing by that name. if you want to save the older file you’re replacing you might wanna move it to an external folder before doing this. Say yes to replacing it if you are asked. (or delete/remove the file beforehand)
7:after doing that for all of the graphics folders. open up the game and boom you should be done.
edit: if this is hard to follow I can add screenshots