You must either make a new colour set, or choose one which has a name (not one of the colour blocks, one of the named ones one the top left).
Click on COLOURS at the bottom of the page (the different tabs that go along near the bottom of the screen, which include info and setup options). After clicking on colours, click on the skin name at the bottom, and choose from the skin list that pops up on the right.
If the skin does NOT pop up on the right, it is either:
1) Not in the SKINS folder (Do not put in skins_x)
2) Names incorrectly (must have the BF1 prefix in the name)
3) Not a Jpeg file, which it must be -or-
4) Corrupt file.
I think that covers it all..
MAGGOT
EDIT - Also, make sure the colour sliders for the bodywork are set to white for the skin to show naturally, otherwise you will have a coloured tint o the paintscheme