There are tons of resources out there for runners. I would suggest using a training program that has been put together and tested. Runners World has some and Hal Higdon has a great one. There are also forums etc and books on the subject. I would do a lot of research first and then find a program you like to follow. I used one of Hal Higdon’s programs and talked with a veteran marathoner for advice and tips when I ran my first marathon.
Check out these: