Be specific, which folder can't you find?
{username} folder just means your windows username folder, people have different usernames, so the folder is named differently. For example if your windows username is RapidFire, then you need to find the RapidFire folder.
AppData is normally hidden, you can go on the "view" tab above and check the box "hidden items" on the right, or press windows key + R to open the run window and type %appdata% in it and press ok, this will open the "Roaming" folder within AppData, so just go back once.
SupaShinKen folder needs you to start the game and probably save your game once, the game will create the folder and put your save files there.