Warm Up: Lunge with a Twist, Knees to Butt, Punter Kicks, Bear Crawls Spend 20 minutes between this and also doing some easy jogging, add some pick ups in.
Once you're nice and warm you're going to run one-mile as fast as you can. This will give you a base line for all of your run work.
Ideally this ride should be done on a trainer as it allows for more consistency, but you can do it outside as well.
Depending on your swimming ability/endurance it might be difficult to swim to this distance. Instead focus on getting through as much of the workout as possible in one hour. All workouts are free style stroke unless otherwise noted.
Swim workouts always have four elements: Warm Up, Drills, Main Set & Cool Down
Drills - you will do the drill and then swim freestyle for 50 yards trying to incorporate the technique you just practiced. You can google all swim drills to see how they are done.
This will likely be the first time that you've ridden your bike for an hour and then attempted to run.
RPM - this is the cadence with which you pedal - ideal is 90+ as it reduces the wear to your quads, and will save your legs for the run. If you don't have a cadence sensor you can time and count your right pedal strokes. 15 seconds @ 22 is approximately 90 strokes per minute. If you've never ridden with cadence this will take some adjustment.
If you're going to do the ride on a trainer, set up your running items close by so you can change and start the run fairly quickly. If you're riding outside, keep it to a loop that will allow you to transition quickly from the bike to the run.
It's assumed that you need to focus primarily on your swimming, so you're going to be swimming twice a week. Again just focus on swimming continuously for the entire hour - don't take 5 minute breaks at the wall.
Just as it is important to swim bike and run, you also need to work on your dynamic strength. Being physically strong will help prevent injuries and improve your endurance.
You should be able to find videos of any exercise for which you have questions. These can be done at home with weights.