I have a spreadsheet with: Column A showing Administration Time, Column B
showing Start Time.

I now need to create an "IF" function that can do the following:
If the total time difference between B and A (column B-Column A) is less
than or equal to 1 hour, then the true statement should be "1", if the time
is greater than 1 hour the result would be a 2, if Column A has text "n/a"
the result would be 3, and if Column B has the text "n/a" the result should
be 4.

I'm not sure how to do and IF command with so many options and that includes
time.

Thanks!