You get a mess of big old quahogs or sea clams (steam open and then chop them up), or some chunks of fresh Codfish, Haddock, or Monkfish - or just a bag of frozen corn.
The base of your Yankee chowder is the same, whether Clam, Cod, or Corn. See Grandma's Corn Chowder for the base (substitute other ingredients for the corn).
You can add a little thickener if you want, corn starch or whatever. Not necessary, though.
My Mom would serve chowda with Bisquick biscuits. Good memories: Mom cooking up a chewy, clam-packed chowder with the basket of quahogs we kids had harvested from the low-tide mud off Great Island in Wellfleet.
Fellow parents: Our job is to build sustaining memories and traditions as best we can, isn't it?