1 and 2: walk at a brisk pace for 5 minutes before your running training. After this, do a quick easy stretch of your calf, hams, quads, and lower back. After running, warm-down with a similar pattern, only allow more time and effort in your stretching.
3: 2.4 KM = 1.5 miles = 7.5 minute mile pace for minimum requirement. This means you need to run @ 8MPH (just under 13 KPH).
4: Run! You need to run a long run (3-4 miles) once per week and then 2 maintenance runs of 1 or 2 miles per week. And then once per week, try running up stairs or doing a hill run training.
Focus only on the things they will test you on (e.g. push-ups, pull-ups, sit-ups, swimming, and running)