As I don't have Facebook I can't really comment on how useful this is, but the Catalyst Demo Team does have a Facebook group:
https://www.facebook.com/CatalystDemoTeam/If there are any Demo Team Agents operating in the DFW area, that would probably be your best bet to get used to the ruleset.
I'm in Houston and I only know of one store that does a beginner's/intro game; personally, I joined the SRMO Discord server in order to start playing some Missions, and the GM and the other players there have been a blast to play with so far.
Best of luck finding a game!