Running

Hope it's ok to ask some newbee questions 🙂 ..thanks in advance for any help!

I did search this thread for "beginner guide" and found this (12 year old : ) post / the two links therein very helpful, also this writeup from the New York Times. I did google a lot as well and, of course, am a bit confused now.

My background, running wise:
have always been running every now and then in the last 15 years, usually for a few weeks at a time, and then stopped / lost interest / did other sport instead.
I always basically just walked out of the door and started running (for about 20-40 minutes, and what must have been like 3-6 km), never really cared about a routine, about stretching, about nutrition etc.

I have not been running at all the last 3-4 years, as I fucked my knees working (meniscal tear in both).

Long story short I / my knees now feel fit enough to run again and I would like to be a bit smarter about it this time.
I have bought the current version of the shoe I had before, as I really loved that (New Balance 1080).
I live in the middle of the city, so it's a mix of asphalt and park paths, mostly the former though.

• I feel that even though asphalt is hard it is a good option for somebody like me who has rather weak knees (always have found that what is making my knees hurt again is making a weird step on sticks & stones -kinda terrain) - so should I avoid the sticks and stones or actually "practice" running on non-flat surfaces?
  
• I see all these beginner's guides recommend a mix of walking and running. This feels awkward to me (I'd rather just run, even if it's just a short duration - can currently do 15-20 mins / about 3km - and build up like that).
  Is that a good idea, or should I really get familiar with the runing-walking mix.
  
• I never had a gps, really don't like having my phone with me, actually I don't even have a watch.
  I feel like a apple watch might be smart idea, for time keeping / for stats, and also for music maybe..
  Is this advisable / are apple watches really good for running-things?
  
• as far as I understood there's no real consensus whether to stretch or not, before or after? So I'd just stretch my legs a little bit after, as this actually just feels "right" to me?
  
• do I understand right that consensus is that little snacks (not meals) before and after are a good idea?
  I did just buy a tin of peanut butter so please tell me I should be eating it
  
  

Thanks again for your help!