Weapons and Armor are usually the next thought a player has after they have arranged for shelter (and night safety) and then food. Maybe third, since obtaining resources and a set of tools are also a concern, but either way you are going to want the best Weapons and Armor that you can obtain, because this is a dangerous world.
In the world of Minecraft Armor consists of the four-piece suit -- Boots, Leggings, Chestplate, and Helmet -- which can be constructed from, in order of protection and durability, either Leather, Gold Ingots, Iron Ingots, or Diamond Gems, with Diamond Gems being the best material for constructing your Armor.
The Armor Helmet Recipe
The Armor Chestplate Recipe
The Armor Leggings Recipe
The Armor Boots Recipe
Regardless of the material you use, the recipe as noted above for each piece, is the same, you just substitute the desired material... The better the Armor the more it protects you, as is indicated by the Armor Level Bar (a bunch of Chestplates). The more of these that are filled the more protected you are.
The Arrow Recipe
Your ammunition for your Bow, Arrows are made using Flint, Sticks, and Feathers, which are very easy to get and stockpile resources. A fully-charged Arrow shot will do 4.5 hearts of damage and there is a chance for it to do a full 5 hearts (less if it is less than fully-charged).
The strength of the Bow is that it allows the player to kill things from a distance, being a ranged weapon, but its weakness is that the player needs to spend time and effort practicing with it so that they are effective with it. It also requires the player to make an effort to gather the resources to make an adequate supply of ammunition (Arrows) for it to be an effective weapon -- so in addition to getting good with the Bow and learning to lead your moving targets, you will also get good at killing Chickens!
The Bow Recipe
The Bow is created using Sticks and String, while Arrows require Flint, Sticks, and Feathers. To use it the player sets it as the active tool in their Hot Bar and then uses the right-mouse-click to charge up the shot, and then you know, actually hit what you are aiming at by releasing the button.
Considering its effectiveness, combining the Bow and Arrows with a carefully built structure that can stand up to attacks like those of the Ghast is a good way to hunt them, since you can attack and then duck back into cover when fired on. Give that some thought. Also consider an Enchantment for your Bow, as they can be Enchanted and that can help a lot.
I know, you are thinking wait, a Snowball is a weapon?! Yes it is! Well, under the right circumstances that is... First you need to know that Snowballs are created when you harvest snow with a Shovel, and as for the right circumstances, this throwable item does not do ANY damage to Mobs -- except in the case of its use versus a Blaze (they deal 3 hearts damage to them) or an Enderdragon (they deal half-a-heart damage to them). So yeah, these are actually a useful weapon!
The Stone Sword Recipe
The basic weapon of the Minecraft adventurer, depending upon what material that the Sword is made from it will do different damage levels and have different durability... Swords can be made from pretty much everything -- Wood, Stone, Iron, Gold, and Diamond -- though Diamond would be the best from both damage and durability.
The Sword is crafted by placing a Stick at the bottom and then two pieces of the base material one in each of the two boxes above on the center of the Crafting Table.
In addition to doing melee damage when the player attacks with their Sword, they can also block attacks by holding the right mouse button. This will block Arrows as well as other projectiles, but will reduce the player to a speed slower than sneaking.
If you ever needed an inducement to get into Enchantment, consider that a Diamond Sword with the Sharpness V Enchantment is powerful enough to kill most mobs with just one critical hit!