when i join a server i get a messages saying skin downloaded. where are they downloaded and how do i view/use them?

Downloaded skins are put in the skins x folder. This is for skins which you dont want to use personally but want to be able to see on other peoples cars. If want to use a skin yourself, it should be placed in the skins folder.

If you want to apply a skin, enter the setup screen for a particular car. Create a new colour, the use the field at the bottom of the screen to pick a new skin file.