Hi Valerie, mostly it's your preference? Usually, all 3 are along the outer edge of the sink -- the faucet in the center. If you're right-handed, you may want the garbage disposal to the right of the faucet. What's the insta hot button ? :)

Ummm I think Valerie means an instant hot water tap for making tea/coffee etc, a normal tap and in the sink, a waste disposal unit ?! - with instant hot taps they need to be placed farthest away - and labeled clearly to avoid scalds - and most people put the waste disposal in the smaller of the two wastes of the sink ( if there's a choice) and the normal tap needs to be placed where the spout can easily cover both bowls ! Hope that helps ?! ;-)