I boiled about 8 potatoes of varying size and type (because some came from my garden and some from the store bag) in way too much water. That wouldn't have been a problem had I drained some, but I neglected to remember that until too late. I think the rule should be to leave only enough water that the tops of the potatoes are peaking up. More than that and it's too watery. My husband equated this to potato gravy.
Then you transfer it in batches into the blender. I wanted a smooth soup so I blended most of it. Sometimes I split it and blend half and mash the rest so I have some potato chunks. I returned the blended soup to the pot where I added salt. I just salt it to taste, sorry, no measurements. Maybe 2 tablespoons. Go easy because you can always add more salt if needed at the table.