First, you have to export the skin. To do that, go in the options, and select your skin. Then, clic on the 'Export as .osk' button.
You will get a .osk file (the osu! skin files).
After that, upload it to an online service like Gooogle Drive or MEGA.nz to store your files.
Then in the website you can get a link to your file. Post this link, so we can get the skin.
Also, it would be nice if you post some screenshots too