When the game was first launched how did the new users know how to craft different objects? The game doesn't seem to have any guide about them.
This could be expanded to any game with a crafting system. It's a pretty common thing. Players just figure things out, either by trial and error, hacking into the source code, or intuition.
Crafting in minecraft is pretty simple as it's shape oriented... for example, a pickaxe is crafted by making a T shape in the grid... even without a dedicated guide/tutorial, new players are able quickly figure it out.
To go through the first hour or so of minecraft that I experienced(and probably many other people):
Player spawns in.. runs around, starts punching things. that's all they can do. Punching a tree got them wood... that sounds useful... open up your inventory and notice a little crafting thing. put the wood into the slot and hey that got the player planks, so they get more wood and make more planks.
After the initial teaching of crafting the player tries again. "maybe I can make the planks into something too" so they put one into the crafting box... nothing.. one on top.. heyyy sticks! Now they've learned items are used to make more items.
fast forward some more and they haven't found a use for sticks yet... but they haven't tried everything with planks, throw more into the crafting box... and look at that.. a crafting table! with a big 3x3 crafting grid, the possibilities are endless!
The player then spends the next chunk of time trying various combinations of what they have with everything (sticks, wood, planks, probably a flower or 2, etc) and since wooden tools are made with just planks and sticks. they can quickly figure out how to make them with a short time of experimenting.
Way back in 2010, during the 'Indev' phase of Minecraft, Notch (Minecraft's creator) announced, on his blog, a patch that included crafting - and gave a few hints to prospective players about recipes:
Crafting on /indev/ now
It’s not very intuitive yet, but it kinda actually works!
Here are some hints to get you started:
Right click with a stack of items to place only one in the inventory. Place two wood tiles so that one is above the other, and you can build sticks. Make a “T” shape out of two sticks and three wood blocks to make a wooden pickaxe.
You can make torches.
You can make emerald swords.
On the same blog, Notch posted a video in which the new crafting was demonstrated. (The video shows a demonstration of very early mining and crafting in the game.)
Essentially this was the sum of the advice given on crafting recipes when the feature was released; players were left to find out the rest for themselves. As part of this, the Minecraft Wiki was created and maintained in the early development phases, where this knowledge was - and still is - shared.
Basicly, crafting is as simple as building,crafting, and speaking. Players experience all of it once logged on to a survival/creative world they maybe saw MC videos or read the discription on the Minecraft home page. Crafting is as simple as all
Crafting: There are variant ways you can make blocks/Materials that are needed or recommended look under this to see 3 things to craft
Since there are 9 spaces on the grid in the crafting table you use those spaces for crafting!
Around the middle space use cobblestone for a furnace... Place wood in all spaces to make wood... Put a gold block in the grid (Anywhere) to regain 9 gold ingots!
I hope this helps you