I don't have amounts of the mayo, parsley or cayenne pepper because it adjusts to amount your making and your taste preferences.
Leave potatoes with skin on and place in a pot with enough water to cover, cook until done, drain and let cool enough to cube, not in small cubes, just quarters if the potato is small and larger cubes if potato is larger.
In the meantime cut your bacon, dice your onion and thinly slice your celery and brown all together until celery and onion are done and bacon is crispy, do not throw out the bacon fat, drain and put to the side. Pour the bacon, celery and onion over the potato quarteres, add chopped parsley, just enough to go through the amount your making (you can use fresh or dried parsley if you like), add I start with 1/2 cup and add a little at a time because it's not to be about the mayo in this one, add some or all of the bacon fat to your taste and add the cayenne pepper, start with 1 teaspoon, just enough for a little kick, stir thoroughly, taste and add a little more of the ingredients to your taste. This is not about the mayo, it's about the bacon flavor in this potato salad. Enjoy.