Break the training into stages, C25k, 10k, HM, marathon. Work back from the marathon- the high milage won't be until after new year anyway. Allow space for life to get in the way: Christmas, holidays, you'll be ill at some point, so allow some slack rest/ consolidation time between phases. This reduces injury risk, eases the mental pressure and gives smaller acheivable goals.
I used Jeff Galloway's run/ walk method of running 60s/ walking 30s to reduce the risk of an injury recurring, and still felt good through the second half of my marathon, and it kept my pace consistant all the way through.
You don't need to run vast amounts. The long run is critical, but another run or two can stay quite short. For completing rather than aiming for time, injury prevention is a priority. Cross training for strength is more useful than an umpteenth run of the week.
Go to a specialist running shop to get trainers that work for you. You'll probably be on a second pair by the time you get to the long run stage.
A good bra, running vest, comfortable pants, and anti-chafe stick will also become invaluable as the milage mounts up. A watch makes monitoring training easier, but Strava is a decent free start. Headphones for podcasts/ music help with focus/ interest too. Bone conductors are good for running as they don't block ambient sound.
Decathlon is a great shop for most basics.
Frequenting the exercise section of MN is a good way to ask questions and chat with others of similar goals.