Pauline, Are you replacing an existing sink? or fitting a new one? A bit more of details and some pics will help you get resposnses for this question. There are some plumbers here on HT who could help.

Some other pieces of information needed are: 1) If you are replacing an existing sink, is the new sink going to be a different depth than the old one? 2) were there two sinks or one sink there originally? 3) did you also change out the counter top and did the counter top height change at all? What is attached to the sink? A garbage disposal? A water filter system? In insta-hot water system? All of these things impact the complexity of the install.