Beginner here, need some advice!

I’m planning on starting my running journey.

I was pretty overweight but have lost and successfully kept off ~24kgs over the last 1.5 years largely by weight training. I used to run on the treadmill initially for the first 3-4 months and eventually tapered down cardio to just 10-12 mins of high incline walking post workouts now.

I’m not shredded by a long shot but have gained some muscle definition

1. I want to start training, usually what is to be eaten and how long before a run

2. I’ve gone through a bunch of videos and I feel I’ve gotten a hang of the warmups that need to be done before. However my back usually feels stiff so anything in particular for that?

3. A friend told me one loses muscle with long distance running, is that true?

4. If anyone is in Gurgaon, where can I go for runs?

Thanks in advance!