Custom skins for items

Hello everyone. Guys, please help me. Please tell me how to add your item's SKIN ID. I want to add my coins to the game, but I can't find how to add them to my workshop. Maybe someone has come across this or someone has a video)

I don't know how to add it to Workshop, but I know how to set the Skin ID for the item. It is taken from the id in the link to the work in the workshop

Item item = ItemManager.CreateByName("coal", 1, 12345678u);
player.GiveItem(item);