Suppose you have 100 entries in your list. Then, for each name you would find the index for it by adding the ASCII values together, the applying mod 100. That is your hash function. So, for example, a student named "Li", consists of ASCII values 0x4c and 0x69. When you add them you get 0xb5 which is 181 decimal. If you take mod 100 then you get 81. So Li should be stored at index 81.

Does that help?

If you're having trouble coding it, please provide whatever attempt you have made so far, complete with compiler errors if you can't solve those yourself, and we'll take it one step at a time.