Can someone tell me the easiest and fastest way to go to Sam Shui Po from Shenzhen east railway?

You must refer to Sham Shui Po in HK, right?
From the East Railway Station, take a taxi to Luohu Port. It costs around CNY 30. The duration is about 10 mins.
Then pass the border and take East Rail Line to Kowloon Tong Station and Kwun Tong Line to Prince Edward Station. After that, transfer to Tsuen Wan Line to Sham Shui Po Station. The subway trip takes around 55 mins. It costs 39.4 HKD per person.