Defined lists are often used to track paragraphs for numbering purposes. When you create a paragraph style for numbering, you can assign the style to a defined list, and paragraphs are numbered in that style according to where they appear in the defined list. The first paragraph to appear is given number 1 (“Table 1”), for example, and the next paragraph is given number 2 (“Table 2”), even if it appears several pages later. Because both paragraphs belong to the same defined list, they can be numbered consecutively no matter how far apart they are in the document or book.

I'm typesetting a booklet that uses a Paragraph Style for a "numbered" list (I'm using A,B,C,D ...). Its probably a simple fix but I can't figure out how once I'm done with one list and move on to the next one later on, to have the numbering automatically restart there, i.e. with A instead of the list continuing the numbering from the previous list. The Mode option under Numbering Style doesn't include this kind of option – I tried the Start At option but this is what I get:
I tried very hard to understand your request, but I still don't get it. When exactly do you want that your paragraph restarts at "A"? After a certain paragraph style (title, list or whatever)? In that case, you just need to create a multilevel list. Please be more specific, using screenshot of what you want to achieve at the very end. – Vinny May 18 '17 at 8:17 indesign-numbering