If it's an .osk file - pink coloured file, you just need to click it.
Otherwise, extract the files in Skin Folder - Right click osu! icon and go to find file location then search for skin. Make sure once you opened the extracted files you should be able to see the skin elements.
[quote="THAT_otaku"]You should be able to double click it to open it. If not, trying dragging and dropping the file into the osu! Window[/quote i did that, but, nothing is popping up, i put it in user and then just put skin user, i know i'm not good at doing these things, but is there a youtube video? they all don't work
Doesnt have anything to do with the user folder in the skin folder. If the download link gives you a zip folder, extract it, then put that folder into the main skins folder and restart your osu. If it gives you a normal folder then put that folder into the main skins folder and restart your osu. If it gives you an .osk then try wht we suggested above again. If none of this worls, perhaps theres something wrong.
The only videos i can find literally just download a skin and then double click the osk file, so they wont be very useful.