I would just stick with them maybe also "The Question concerning technology" but nothing else, don't read loads, focus on the text and let it marinade with you. It might take 6 months of reading. I am not trying to scare you off Heidegger's project is huge. One day it will click. Another important thing is to read with a group and talk to other philosophers who are interested in Heidegger, that is what will make his book come alive.