Introducing whole milk

Any tips on how to introduce whole milk? My son just turned 1 last week and the doctor said if I’d like to start introducing milk to him I can. Last night I finally went to go buy some, but I don’t really know how to introduce it. Do I just give him a cup, do I dilute it with water? Is there a certain amount of oz a day? He still is breastfed. A friend of mine mentioned doing half breast milk and half whole and gradually take out the breast milk. The problem for me is last month I stopped pumping so I don’t have any frozen. I do produce still so pumping is still an option…. I just want to see how others went about doing so.