Hi Buster, I know the feeling, when I first picked-up my Stoker I was looking for direction on using the Stoker and then Stokerlog. I started laying-out a beginners guide based on what I'd learned by trial, error and the advice of other stoker users on this site but it hasn't gotten past layout phase. I have several long flights coming up over the next 60 days so my hope is to spend my downtime on the plane moving this project forward.
With that said, I'm not aware of any documentation other than what you'll find here on using Stokerlog. The system is pretty intuitive and easy to use/figureout. My biggest challenge was finding info on how to build my fire, vent position, clay saucer or foiled pan etc. Honestly, Stokerlog was probably the easiest part of the setup.
To answer your questions regarding firmware it Stokerlog does run on a pc.
I know I've asked tons of "dumb" questions regarding Stoker, Stokerlog and Stokertimer, it might be helpful to read posts in this area that were started by me. I received excellent feedback and help from the Stoker vets on this site. If you're not finding your answers just ask the question here. Lots of good help available.