DIY is a great and a really interesting art, however before you attempt any job you should always know your limitations and don’t feel too bad if you don’t think that you are able to cope. There are many professionals out there like Hampstead Plumbers ready to help you.Note:When you come to fit the new sink, it should most times fit well in the pre cut countertop opening, but a good idea is to test-fit the sink and check that it sits level. 1). Spread plumber’s putty around the sink’s plughole and set in the strainer assembly. Turn the sink upside down and then tighten the drain nut and “tailpipe” piece. Put the sink upright and install the taps, valves, and handles. Tighten down these items and connect up the water lines to a T- type fitting. You can also connect up the water lines coming into the valves and avoid doing that once the sink is set. 2). Place the sink in the cu-out and secure any supplied mounting clamps underneath it. Put a bead of sealant caulk around the edge and should the new sink not be of a self-rimming type, then, run a bead of plumbers putty as carried by a Hampstead Plumber on the bottom of the lip and caulk the opening to keep it watertight. Seat the sink and tighten any clamps.3). Take out any packing you have used to block the drain whilst carrying out this job. Screw on a trap to the adapter threads and sink drain. Screw on water supply lines (if you haven’t already) and attach them to the shut-offs. Use a “two-headed” shut-off if you’re also going to connect to a dishwasher. 4). Finally it is good plumbing practice to run water down the drain to block sewer gases, and check each line and drain joints for leaks.”