Wow. Weve got a lot of new triathletes on this board!!
Here's what I recommend for my new triathletes. Start out with a sprint. Try to get in 3 runs a week, 1 easy 30 min (even a run/walk is fine), one where you focus on form, one longer one. That one would be your longest run and will get longer each week by 10 to 15 min until you reach your race goal distance plus 25%. 2 to 3 swims and bikes per week. As you get better you want to increase your number of bike workouts because that's where most people can gain the most speed/time on race day. But for beginners it's all about getting comfortable in the water and getting a little fitness and reserve on the run.
I always recommend an easy week every 3rd to 4th week, depending on the athlete to recover a bit from a tight schedule. And in the last 1 to 2 months before your event you should be doing bricks (a bike followed by a run) and practicing transitions.
Hope that helps.
Living life like there's no tomorrow.
http://gorgebikefitter.com/
2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS