Welcome!
First off, here is a hub for deathmatch/ mge (1v1 training mod)/ jump/ surf servers: http://www.teamfortress.tv/servers
You'll find that you want to just play pubs a bit to get used to the class roles in the game, along with aim mechanics. After a few hours of doing that, you can head over to newbie mixes, which happen every friday at 9 est: http://steamcommunity.com/groups/na6v6newbiemix
There are various pug services (both in house and public), but those are generally designed for players with a few hundred hours in the game but little competitive experience.
Here's a really solid guide on getting into it all:
https://www.youtube.com/watch?v=o15AaDYvyWE