I am new and kind of lost, I am following the questing just fine but I want to go into dungeons, are they all 50 people? Second what are hero points and where can I go to find a guild, Is there someplace players hang out?
No dungeon needs 50 people. They're made for parties, which have a maximum of 5 people. There's also raids and strike missions (mini raids) which are harder and designed for groups of 10 people. Player squads can hold up to 50 people, but that's because they're used for open-world activities and World vs. World which are designed for a lot more people working together.
Hero points are what you use to unlock skills and specialisations (from level 11 onwards). You get them by levelling up or by completing hero challenges in the world and once you're level 11 you can use those points to unlock new things in the build tab of the hero menu. (Levelling up to 80 will get you exactly enough hero points to unlock all the base skills and specialisations. Ones earned from challenges let you unlock things faster, and after level 80 any points you didn't use for core stuff, plus any new ones you earn can be used to unlock elite specialisations.)
There are two ways of finding a guild: one is to look in this section of the forum: https://en-forum.guildwars2.com/categories/looking-for-guild. The other is to ask in-game. If you go to a city like Divnity's Reach or Lion's Arch there will probably be people advertising, or any busy map. You can also ask in map chat if any guilds have an opening.
If you want to find people to do group activities you can also use the Looking For Group tool in the game. It can be used for all parts of the game, not just dungeons and raids. Unlike some games it won't simply dump you into the first group with an opening - anyone who creates a listing can write out what they're looking for, and then you can choose a group to join. If you don't see one for the activity you want to do it's always better to advertise yourself than wait for someone else to do it. Putting up an advert does not mean you'll have to lead the group or that everyone else will expect you to know what to do, it just lets them know you're looking so they can join.
Also your server is only important for World vs. World. For everything else in the game maps are shared between all servers in the same region (North America or Europe). So you can join any guild which says they're on an NA server, and play with anyone else in NA, you don't need to worry about finding people on your specific server.
Danielle Aurorel, Desolation EU. Mini Collector
"You can run like a river, Till you end up in the sea
And you run till night is black, And keep on going in your dreams
And you know all the long while, It's the journey that you seek
It's the miles of moving forward, With the wind beneath your wings"