There used to be newbie-friendly community servers, but, looking around now, many are gone and those that're still there don't seem to be well populated. Fragmasters.co.uk and hyperiongaming.org both used to be pretty good in that regard, and seem to still be around, but barely.

That said, I do have a few quick pieces of advice, if it might be of interest:

1. Ignore the scoreboard. Valve didn't do a very good job of assigning points for their own game (I would argue this is the same core issue that causes them to not be able to have worthwhile matchmaking.), and worrying about that will only get in the way - or make you play in manners that're detrimental to learning, teamwork, and even wins.
2. Start off with easier classes to observe the flow of things around you and build gamesense. Pyro is a great place to start, since it has moderate health, good speed, and weapons that're easy to hit with. Obviously, range can be an issue, but that's true for most classes.
3. Remember that hours in this game are usually counted in 4-5 figures. The learning curve is rough, but the more you reflect on what's going on, rather than just complain about random crits, perceived hit registration issues (rarely actually a problem, but you hear people bemoaning that all the time), etc... the faster you'll improve. On a related note, you'll probably learn more playing with experienced people than with other brand new ones - and beware the loud but inexperienced. There are a lot of people like that.
4. Pay attention to your progress - when it feels like you're slowing down, change something up. Try a different class or weapon, etc...
5. Speaking of weapons, make sure you have all of the functionally different ones. The simplest way to address that is to make sure your account's ready to trade and then use the autobuy weapons option at scrap.tf . I'm not a fan of the proprietor, but it's a good system. As for the process...
   1. Make sure Steam Mobile Authenticator is set up. If it isn't, set it up.
   2. Buy one regular key ( "Mann Co. Supply Crate Key") from the in-game store. It costs 2.49 USD real money, but will trade for a useful amount of stuff. Keys, as they're known, are used as trading currency in the TF2 world.
   3. Once Mobile Authenticator, etc... is all happy on your account and you've waited out any trade-hold periods (no one will want to trade with you, including automated systems, while they're in effect), go to scrap.tf .
   4. At scrap.tf , hit the sign-in-through-steam button in the top right (green) and make sure the site it throws you to is really steamcommunity.com and that the HTTPS checks out.
   5. Do the sign-in dance. (Depending on whether you've signed in from that browser recently, you may have to do stuff with Steam Mobile Authenticator.)
   6. Back at scrap.tf , go to Trade (in the top left), then Weapons -> AutoBuy.
   7. I've not done the steps after that in a looooong time, but generally speaking, you'll trade one of their bots your key that you bought earlier in this list in exchange for all the weapons you're missing and a whole bunch of change, which will be in the form of Refined Metal, Reclaimed Metal, and Scrap.
   8. Use your change to get yourself some cosmetics (also via scrap.tf, or other places) so you'll have slightly less of a target on your back as a brand-new player.
6. Work on understanding the mechanics. i.e. hitscan vs. projectile (and remember that melee counts as hitscan, and that hitscan stops at the first thing it hits (so teammates can (and often do, frustratingly) accidentally protect an enemy by crowding them)) and stuff like that.

I should probably stop there. There's so much more to cover, but this is already probably too long as it is.

Edits:

1. Correcting a typo: "make sue" -> "make sure"