You'll normally be able to use your existing water supply pipe and waste outlet when you replace your old basin or sink. Try to choose a trap that's similar in size to the one you've taken out, as this makes fitting it a lot easier.
If you're replacing your existing sink, measure the space carefully. You may need to extend nearby hot and cold water supply pipes to connect them to the inlet pipes of the new taps. You might also have to extend the existing waste outlet pipes to meet the trap of the new sink before you install it.
Flexible push-fit tap connectors are pretty simple to fit. Some have built-in isolating valves that mean you can change a washer without turning off your whole water supply.
Start by putting the tap together according to the manufacturer's instructions, and attaching the pipes to the correct inlets.
Fit the retaining clips to the underside lip of the sink, spacing them evenly. Then run a continuous bead of sanitary silicone sealant around the outer edge. After that, carefully turn your sink over and rest it in the cut-out in the worktop. Working from the underside, tighten the screws on each retaining clip. Take care not to over-tighten them, though.
Now it's time to put together the waste pipes and trap. Put rubber O-rings on the waste couplings.
Fit the waste coupling to the outlet on the underside of each sink bowl.
Join the hot and cold water supply pipes to the tap pipes with flexible push-fit tap connectors. Then connect the overflow pipe between your new sink's overflow outlet and the inlet below the bowl. Finally, turn on your water supply and check for any leaks, retightening the joints as necessary.
Kitchen surfaces are cleaned a lot, and are often left wet. That's why it's wise to seal all the joints, particularly along the back of a worktop and around the sink. Sanitary silicone sealant is easy to apply, forms a flexible waterproof seal and stops any water from penetrating.
Use the template provided with your sink, or turn it upside down on the worktop (with the bowl in the right position - the sink might not be exactly rectangular). Make sure it's an equal distance from the front and back edges and that it fits into the base unit underneath. Trace its outline directly onto the work surface in pencil. Or, if your pencil won't mark the laminate, stick masking tape on the surface beneath the sink edges and trace the outline onto it.
Drill a hole through the worktop at each corner of the inner line with a 12mm gauge flat bit. You'll be able to slot in the blade of a jigsaw - but be very careful that you don't stray over the line.
Cut along the inner line, using a power jigsaw with a laminate blade. There are a couple of things to remember here. First, it's a good idea to stick masking tape on the jigsaw plate to avoid scratching the surface. And to stop your worktop from splitting, try to support the piece you're cutting out as you get to the end.