The best explanation I have read about the zone system and what it all means is in Bruce barnbaums book. All of the fancy explanations with numbers and other things that mess with our dyslexic minds is not there. It is very user friendly and very well explained.

http://www.barnbaum.com/artofphotography.html

Since you are using a MF camera there are issues with development that can be overcome with multiple backs loaded with BWQ film and designate N, N-, N+. Welcome. This is a great place.