If you want a healthy version buy some new potatos. Peel and boil in enough water just to cover them till firm but not mushy soft.
In another pot cook some filets of sole with a can of clams including the juice and add some fish powder/essence to taste. I think you can buy in Park N Shop - definitely in the Sogo grocerey store in CWBay.
Once the potatos are done then you can mash them roughly - dont make mashed potatos, what you want is a chunky mash.
Once the fish is cooked you can combine both into one and simmer for an hour or so. Then let sit ideally overnight (although you can eat right away if you like)
The potatos will give the chowder chunkiness and they also will thicken the soup so need for cream or whatever it is they put into canned versions to thicken it.
You can find a recipe for anything (except nuclear weapons) on the net - just go to google or wahoo and type in search for "xxx recipe" and you will get more than you can handle