Every starting zone has an area that serves as an introduction to crafting. Each city also contains a crafting area as well. The wiki is the best place to figure out where the trainer NPCs are.
As a bonus, these NPCs will also sell you salvage kits and other useful tools.
At first, it might seem a bit daunting due to the game’s Discovery system, which allows you to uncover unknown recipes for items and in turn rewards you with massive amounts of bonus xp, but if you follow guides on gw2crafts, it’ll be easy.
I recommend leveling armorsmith (heavy armor), leatherworking (medium armor), or tailoring (light armor) on your first character. If nothing else, you’ll be able to craft a few useful things for yourself using these, including bags and an upgradeable back item with selectable stats. The level 78 one includes an infusion slot so it’s useful for players who need another agony slot for fractals on a budget. Cooking (up to 400, at least) is a cheap option, along with jewelcrafting.
There are certain items that may only be crafted once per day. Some of these are materials required to craft Ascended items, which have the best stats in the game. Here are a list of time-gated recipes. You should also charge 25 quartz at any place of power every day. The easiest ones to access are the one within your home instance if you have the Krait Obelisk Shard or right outside Lion's Arch at Durmond Priory [&BOkAAAA=]
For bags, a free-to-play player is limited to the starter backpack (20 slots) and two additional bag slots. If you are in this situation, I would advise you to use standard bags (ones that do not sort your items in a particular manner. Review the wiki for more information).
You’ll have access to four bags total in addition to your starting backpack if you are not on a free-to-play account, which gives you some flexibility on how to handle your inventory. I recommend having three regular types of containers and one invisible bag/safe box. That way you can keep important items in the safe box without fear of accidentally salvaging or selling it off. As a reminder, items in an invisible bag/safe box will not move when using the “Compact” option in the inventory nor will materials be deposited when you click “Deposit all materials”. You still have the option of right-clicking each material and depositing it that way.
New players are often overwhelmed by the number of items thrown at them early on and may quickly run into inventory management issues if they’re not sure what to do with everything.
Junk - For all items with a grey name, those can be sold to any merchant/vendor that has a sell tab. You are able to click on “Sell Junk” and it’ll offload those items for you.
Event - feel free to destroy them unless the event is still going on.
Salvage - These items, along with gear that you do not wish to use/are no longer using and pieces of unidentified gear (should be identified first), can be salvaged by using a salvage kit. Please refer to this wonderful spreadsheet to decide on which kit to use. The author states that Copper-Fed can be replaced by Basic and Silver-Fed by Mystic (best) or Masterwork. As a tip, a mystic salvage kit can be created by going to a mystic forge and throwing in a Fine (blue), Journeyman’s (green), and Master’s (Yellow) salvage kit along with 3 mystic forge stones which are easily obtainable from regular play. I do NOT recommend spending gems on stones. It has 250 uses and it should take you a while to get through one. You will likely be carrying multiple basic salvage kits with you at all times since each one is only 25 uses. If running a dungeon/fractal, you will probably want to have 2 to 3. Copper-Fed in a shared inventory slot is the best option if you’re looking to spend gems on a convenience item, but it’s not a necessity.
Crafting materials/Containers - If you have any containers (supply bags, etc), you may open them to receive crafting materials. There’s a nifty feature at the top right of your inventory window that allows you to instantly transfer all crafting materials that are in bags (unless it’s in Invisible Bags/Invisible Packs/Safe Boxes/Courier's Bags) into a special Material Storage section of your bank. Make sure to refine your materials if you have leveled up your crafting enough in order to save room (ex. Turn iron ore into iron or steel ingots). By default, you may store up to 250 of each material within material storage.
On a side note, “Hide bags” is a convenient feature if you like your inventory to look like one large container by hiding the separated borders, but it makes it more difficult to spot which slots belong to invisible bags, etc.
The mystic forge is a crafting station that may be found in a variety of areas. The most common location is within Trader’s Forum in Lion’s Arch. Throughout your journey you will encounter items that may only be crafted at the Mystic Forge, or you may use it to upgrade crafting materials to the next tier or get rid of equipment that is not salvageable/tradable. It also allows you to change your stats on ascended equipment. Since there are so many uses, please refer to the wiki article to see the recipe list.
For most new players, you’ll likely use it for mystic salvage kits (3 mystic stones, 1 fine, 1 journeyman’s, 1 master’s salvage kit) and to convert equipment received through level-up rewards (usually unable to be salvaged/traded) into something useful or at least salvageable/tradable.