Adding Time (Duration) to Dates

Hi all! New to Alteryx so please excuse a potentially simple question. 

I am trying to take various appointment periods (some 2 hrs, some 40 hrs) and determine if an individual was more broadly supposed to be at the office that morning or afternoon. 

Basically, I'm trying to turn this (assuming 2, 4hr blocks per day)

into this:

Any tips/suggestions would be greatly appreciated! Thank you all!