More detail on each area
How the coaching runs month by month, who it is for and what it costs is set out in full on the triathlon coaching page. If what interests you most is how the planning itself is built — and why off-the-shelf plans usually fail — that is covered under training plans.
Depending on what you are working towards, it may be worth going straight to the point: for 3.8 km, 180 km and 42.2 km there is a dedicated page on long-distance triathlon, with separate sections for your first finish line and for a new personal best. If you are right at the start instead, the page on getting into triathlon takes you step by step to your first race.

