Are you wanting to reverse the order of the spreadsheet column that you’re retrieving in the GetColumn block or are you wanting to add a new list item to the top/start of the list in the "in list [app selectedList] insert at] block?
If it’s the latter, change “insert at [last]” to “insert at [first]”.
If it’s the former, I suspect you’d have to write a function to retrieve the column as a list and then to re-order everything in reverse order (in a list of n items, move item n to top/first item of second list --> change n to n-1 --> repeat)
The built-in list functions only support sorting by numerical or alphabetical order.