periodocity

Wow ... those are the central questions to building a training schedule.  The fact that you are asking them means that you have developed a sufficient understanding of the tenets of training to get an idea of knowing what you do not know. (This took me much longer and a few injuries before I started to grasp the concepts.)

At this point you need to make a decision: how do I plan to learn the answers to these questions?  Will it be through reading books like Friel's or Matt Fitzgerald's Complete Triathlon Training book and then trying to apply what you learn there into building a scheduled?  Alternatively you can hire a coach, have them build your schedule and learn through this process.

I tried the latter and fumbled my way through a season of trial and error ... and a couple injuries.  Had a great time doing it but was often frustrated by not wresting the results expected given the amount of effort placed into the training.

Understanding then what I did not know and facing an iron distance event, I bit the bullet and opted to hire a coach - Atlanta based pro-triathlete and uberswimmer Carole Sharples (www.carole-sharpless.com).  I knew that the distance required more than my basic understanding.  

Since then I have learned through the training as she has explained the basic tenets of why I am doing particular workouts.

If you opt to go it yourself then plan to read through one of the books (both at this point would be overkill) and take notes.  Each has a sample training plan that you can tailor to your needs.  As you read the book, the answers to your questions will become evident.  More questions will arise when you build your schedule. Post them here as BT is an awesome resource ... but remember that you get what you paid for (people who answer will have varying depths of experience and focus).

There is no right, 'one-size-fits-all' answer to the question of whether to build your schedule yourself or avail yourself to the services of a coach ... it all depends upon your expectations, goals and amount of effort/persistence.

On 8/20/08 their was a thread on the GA forum regarding tri coaching - you can check it out:

http://www.beginnertriathlete.com/discussion/forums/thread-view.asp?tid=129116&posts=10&start=1