I just ran up a hill and then 2 blocks and I am having so much trouble breathing, what should I do to train?

Alternate walk/run. Week 1: walk 30 minutes mwf, week 2: walk 5", run 30 sec, walk 2", repeat for a total of 30". Week 3: walk 5", run1", walk 2"-repeat total 30". Week 4: walk 5", run1.5", walk 1.5"-repeat total 30". Week 5: walk 5", run 2", walk 1"-repeat total 30". Continue this pattern, you'll be amazed and how quickly you build endurance.