Though it may take a day or more, installing a kitchen sink is well within the ability of even the amateur do-it-yourselfer.
Some care, a bit of patience, and a few guidelines are the only basic prerequisites.
Clear out everything under the sink to provide working room and space for some towels and a bucket. Then turn off the water valves under the sink. If, for some reason, they're absent it will be necessary to turn off the water main for the whole house. Turn off the circuit breaker that controls the garbage disposal.
Open the faucet and run the garbage disposal for a second or two, to clear out as much water as possible. When you remove the hoses attached to the hot and cold water, as well as that to any handheld sprayer, be prepared for some drippage.
Now remove the U-shaped pipe (often called a trap or trap bend), followed by the straight pipe that is directly attached to the sink. Remove the garbage disposal by first disconnecting any wires and dishwasher hose. There's a large ring retainer that will need to be removed from the unit's neck as well.
From the top of the sink, work loose any caulk and plumber's putty that is keeping the sink in place. This will be tedious because it has to be done with great care. The odds of scraping the cabinetry or countertop are high. Go slowly and keep control of the utility knife to avoid any scrapes. Work it all loose a little bit at a time.
Once the caulking and plumber's putty between the sink and cabinet/countertop is loosened the sink can be pulled free. Most people will want to replace the faucet and controls when replacing a sink. But if you plan to reuse them, they're easier to remove once the sink can be turned upside down on the floor.
Before placing the new sink in the hole, some preparation is required. This is an extension of that same tedious work as before, but it's vital. Remove any remaining caulk and plumber's putty so you have a clean, smooth surface around the rim of the opening.
A combination of utility knife scraping and sanding will probably be necessary. It isn't fun, but it's the only way to guarantee a good seal for the new sink. Drips of water that move between the sink or countertop to the cabinet below creates mildew, foul odors, and ultimately a weakened surface where you store household cleaners.
Tip the new sink upside down to install the flange. Place some plumber's putty on the underside surface of the flange and have an assistant push it up into the sink. From your side, place the retaining ring/nut and tighten it down. Then turn the sink back over and remove any excess putty squeezed out. Allow the putty to set for an hour or more, according to the directions on the can.
The rest is very straightforward.
Simply apply plumber's putty to the rim and gently drop the sink into place. Again wipe up any excess from around the rim and allow the putty to set. Then replace the hoses and pipes. When you replace the pipes be sure to wrap Teflon plumber's tape in the direction that will squeeze it into the threads, not loosen it, when you tighten the slip-joint nut.
Attach the garbage disposal unit onto the sink flange and tighten the retaining ring and/or nuts into place. Replace all wires and the dishwasher hose. Test the new sink for drips before turning back on the circuit breaker.
To test, just open the cold water valve slightly and open the faucet. Allow the water to run for a minute and watch carefully for any drips. Any leaks will usually be the result of incorrect plumber's tape application.