If you are in Sheung Shui KCR station. You can take kmb 276/276a/b/p.
Note 276/276p can only reach Tin Tse Estate which is in the southwest of Tis Shui Wai.
for details plz go to
http://www.681busterminal.com/ssfl.html
(You may also take 902r, the non-franchised scheduled bus (from Kingswood Villa to Sheung Shui KCR station) operated by Kwun Chung Bus Ltd.)