How do I fix this simple R loop error manipulating lists

Question

Basically want to input 2 lists and one is a list of total_values = [41,42,40,37,42,..] and the other list is a list of length the sum of the values in total_values, say 700. Call that list set_values. I want the index of each value in total_values and make a new list to return. So I want the new list to contain set_values[41] as the first value. set_values[41+42] as the second value. And set_values[41+42+43] as the third value using the indexed position from total_values. I have try to do this with a nested for loop to increased through the index of total_values but I have no luck and very frustrated... Please let me know if you have any good advice it would be greatly appreciated!!