Hi, in order to install the skin you have to put it in the "av8bna" folder in "saved games" located in
C:\Users\"your user"\Saved Games\DCS.openbeta\Liveries\av8bna
after you install it it should be like:
C:\Users\Misha\Saved Games\DCS.openbeta\Liveries\av8bna\IM@S HIBIKI
Warning for you it might be just "DCS" and not "DCS.openbeta" as im using Open beta