1) Instal 'Visual Novel DS' as normal 
You should have a '/VNDS/' folder on your root
2) Extract all 3 files into '/_dstwoplug/' folder
3) RENAME the '/VNDS/' folder on your root to '/VN/'
4) DELETE any other copies of VNDS.NDS (other than the one inside '/_dstwoplug/' folder) as these WILL NOT WORK