The 24 week couch to marathon training plan is designed for novice runners and people without much of a running base;
It's designed around 4 distinct phases:
i) the 5k
ii) the 10k
iii) half marathon
iv) the marathon
After you complete each phase (which cumulates with running the target race distance), the plan is designed such that you can take a pause from the training plan and do interim training weeks with lesser mileage, before starting the next phase.
The 4 Hour marathon training plan is one of my most popular training plans, and has been used by hundreds of runners.