Need training help back after 25 years

Ok I started riding again after twenty-five years back in spring of last year but because of work and the cold I stopped. But now it is time to get serious. This past Saturday & Sunday I did twelve and seventeen miles. This is on a road bike of course. I have no idea what I am doing for training. My goals are to build stamina and speed so I can ride in half and full century rides. I am forty-seven years old and about twenty pounds over weight. Our there any good training books, video that will get me started in the right direction? I need to learn things like how should I eat before and after workouts, how many days should I train? And what type of trainning I did purchase an indoor trainer and a heart monitor. Any advice would be greatly appreciated 🙄