Refrigerators usually come with two humidity settings in the crisper drawer: high and low. The low humidity drawer is for things that get moldy easily. The high humidity drawer is for things that wilt easily.
Generally, the high humidity is for leafy things; on your list, the parsley, celery, and basil. You can also keep things that wilt, like the zucchini and carrots.
The low humidity is for other stuff. On your list, that would be the apples, oranges, and peppers. Berries of all sorts definitely go in the low humidity drawer.
The potatoes and onions really shouldn't be refrigerated. They should be kept in a cool, dark, ventilated place. They'll actually get moldy faster in the high humidity of a refrigerator (even the low-humidity drawer).
People are of mixed opinions about peaches and kiwis. I say they shouldn't be refrigerated, but if you do refrigerate them, keep them in the high humidity drawer. It's better if you can keep them on the counter and eaten within a few days.
Anyway... you really only need the high and low settings on the slider. The slider lets you have two high, or two low, or mixed, depending on what you have on hand.