The trick is to cut them into bigger chunks than usual, because they'll break apart more when you start mixing. And mix as gently as you can.
This isn't my go-to recipe, but it's got the main points covered. This version was based on what was in my refrigerator and what I was in the mood for. All the measurements are estimates. Use your own judgement, and adjust to your taste
Russet Potato Salad
cider vinegar, about 1 teaspoon.
sweet pickle relish, about 2 tablespoons
roasted red pepper, diced, about 1/4 of a pepper
brown mustard, about a tablespoon
mayo, about 1/2 cup, and more as needed
Greek-style yogurt, about 1/4 cup
frozen peas, about 1/3 cup
Peel the potatoes as soon as they're cool enough to handle. Chop them into large chunks (believe me, you'll have small pieces when you're done) and put them into a mixing bowl. Sprinkle with salt, to taste, and sprinkle on the cider vinegar. Let them cool to room temp before you continue.
Pile on all the ingredients, and mix gently. Taste for seasoning, and add more mayo (or yogurt) depending on how creamy you like your potato salad. Refrigerate for at least an hour before serving.