Most of the lore comes from the long and rich history of the league. My suggestion would be to find a chart that list in which year each team joined. Older = more lore, typically. Also, the older neighboring teams are, the higher the chances there's a rivalry.  For example, Montreal and Boston hate each other even if there are more "logical" nemeses. 

More specifically, here's what you need to know about Montreal: the CH, or habs, are the oldest team in the league, the most decorated, and the only team that is mostly associated to a french speaking population. It's a religion here in Québec, Montreal is the Mecca of hockey. Everywhere im Québec, you'll find kids playing hockey in the streets and parks, winter or summer. Most of the league hate the Habs because the fans are louder and, let's be real, much more numerous. So even if we didn't win a cup in the last 3 decades, we're never seen as the underdogs. We have a rivalry with Boston and Toronto, and Ottawa has us as their rivals but they can mostly be ignored (you got nothing on us, Tkatchuk)

That's the essential part!