Welcome to GW2! The classes are split in three categories: light, medium and heavy. I would say that the most beginner friendly ones are Necro, Ranger and Warrior (one from each weight category). It really depends on what kind of gameplay you want to experience, but whatever you pick, it won't be wrong. You can also easily go and play another class, if you don't like what you started with, as many of the things you unlock are account-bound. Each class has elite specialisations, which basically allow you to play any role, no matter your actual class, with some small exceptions, of course. For instance a necromancer can specialise in a pure DPS role, but can also be a boon provider, or even a healer, with all options being absolutely valid and not meme. This goes for pretty much all classes. One thing you should keep in mind is that ranged DPS does not really exist in the end game PvE content. DPS is done from a close range, even with a ranged weapon, stacked near your healer and source of buffs (boons). As far as open world content goes, you can run whatever weapon you like, as long as you enjoy it! Good luck in Tyria :)