Here is another really good resource for beginning deck building, I started playing the game only a few months ago and this proved to be invaluable in helping me understand the key concepts of the game (and for creating my initial dual-sphere decks).  In the blog Mr. Beorn goes through each of the core set quests using only core set cards and provides in-depth analysis on the cards included in the decks he built.  He continues this through the entire Shadows of Mirkwood AP cycle, adding new cards from each AP into the deck as he progresses.
 
http://hallofbeorn.wordpress.com/beorns-path/
 
As a side note, I honestly wouldn't pay too much attention to the fact that a "tournament legal" deck size is 50 when all you have is the core set.  With only the core set, the card pool is so limited that I find it silly to artificially inflate a deck to 50 cards by including bad and not-very-good cards.  This isn't a game where you play competitively against other people, so unless you want to immediately start comparing scores with other people, starting with a deck of under 50 cards is just fine.  If you stick with the game and really love it, I would gradually up your deck size as you go through the AP's because by the time you get through the Shadows of Mirkwood cycle you'll have plenty of cards at your disposal to flesh out some decent 50 card decks.

I ordered the first expansion
 
I have to say the article from BGG is super useful, i tried the "illegal" deck and i won the first adventure, but it wasn't easy, the game is amazing.
 
Rule question, Snowburn scout put a advancement token in a location on staging, that means tha the location become immediately active as the group has traveled there or it stays in staging and another location can be chosen to travel?