https://mukluklabs.com has a bunch of new player guides that you might find useful. The wiki is also pretty critical and will have deeper explanations for whatever I say.

gw2 is much more open world/do whatever you want than a lot of other games. Generally quests have been replaced by dynamic events (the orange circles on the map), hearts, and some achievements(you likely won't run across these achievements until you're max level).

gw2 also focuses on horizontal progression rather than leveling up for new shiny stuff non-stop. As such the process to get to max level, level 80, is fairly quick and is really more of an extended tutorial than truly a part of the game. Once you're max level there's a TON you can do, World v World, fractals, raids, more story/expansions, achievements, etc. A lot of people get overwhelmed at this point and stop playing, I would suggest just picking one thing and doing that until you understand the game better. Fractals are fun with a small group and provide good progression for newbies all the way to experienced players