How can assign a index to a list using list blocks?

i am trying to assign a index to a specific list that i add using creating empty list or make a list. but i dont know how to call when i add the element to a list

lists_add_items
This adds item 1 to an empty list.

If the list already has 1 item, it adds item 2.

New items go on the end.

Use index of thing in list:

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