To use:

Please backup your "c" folder before installing.  Place the contents of the Unskirt Mod folder into your Kuro no Kiseki folder.  It should ask you to overwrite 47 files if you are copying to the correct place.

To use the bonus Shizuna bikini costume:

Identical to above.  It should ask you to overwrite 1 file, chr5117.mdl.  Please note it will overwrite the Shizuna mod from Unskirt mod.  To switch back, copy the chr5117.mdl file from Unskirt mod.

Enjoy!  -amorrow28
(This should have been a free download from loverslab.com)