Python question. Find the smallest alphabet, the third smallest alphabet, and the most common alphabet in a given string.

I am a student who is learning Python 3 in school class. I received my school homework, but I don't know how to start, so I post a question here.

1. Write a function, q2(inputString, minLetter), that takes as input a string of letters and returns six things: the lexicographically smallest letter (z/Z > y/Y > ... > a/A) greater or equal to minLetter, the smallest index at which that letter occurs, the third smallest letter greater than minLetter, the smallest index at which that letter occurs, the most common letter, and how many times the most common letter occurs. The third smallest letter must be distinct from the second smallest which must be distinct from the smallest. E.g. 'b' is the second smallest and 'c' is the third smallest in 'ababdc'

Ignore case during computation. E.g. 'z' and 'Z' are considered the same letter. Use lower case when returning letters.

Return None for smallest and thirdSmallest letters and corresponding indices when appropriate.

You may not assume that the input string contains at least three different characters (or even any characters at all). Make sure to recognize various situations where fewer than three different letters appear in the string, and where there is no third smallest or smallest greater than minLetter.

If two or more letters tie for most common, return the lexicographically smallest one.

For example:

>>> q2('aacyYcqyQQqyqc', 'b')
('c', 2, 'y', 3, 'q', 5)

>>> q2('aacyYcqyQQqyqc', 'r')
('y', 3, None, None, 'q', 5)

The question is this, but I don't know what to do because the school told me not to write down the list or Sort. It's my first time learning Python, so I don't know what it is, but I'm worried that it doesn't teach me well in class. Python masters, please help me.

I only made two lines of code right now, but I don't know how to approach it.