There are many Biomes in Minecraft. A biome is a specific part of a Minecraft world that has materials that differ from other parts of a Minecraft world. Some examples of Minecraft Biomes are: Plain, Desert, Jungle, Forest, Ice, Snow, Swamp, Mushroom and Birch. All these different Biomes make up the Minecraft world you can find different kinds materials in.
Some examples of the different types of one specific material are: Birch wood, Oak wood, Dark Oak wood, Acacia wood, Spruce wood, and Jungle wood. Many Biomes include many interesting materials. In Desert Biomes you can find temples and many different things like caves and sandstone villages and mobs. The rarest things to find in a Minecraft World are: Ruins, Shipwrecks, Temples, Strongholds, Ocean Monuments, Mesas, Nether Fortress, Wither Skull, Giant Mushroom, Nether Star, The End, Elytra, Pink Sheep, Diamonds, Emeralds and Netherite. There are so many more interesting things that you can find in Minecraft!
There is many dangerous & even friendly mobs in Minecraft. Examples of dangerous mobs are:Creepers, Zombies, Endermen, Skeletons, Drowneds, Gaurdians, Elder Gaurdians, Silverfish, Spiders/Cave Spiders, Ghasts, Zombie Pigmen, Wither Skeletons, Wither, and Ender-dragon. Examples of friendly mobs are:Iron Golems, Snowmen, Villagers, Cows, Pigs, Sheep, Mushroom Cow, Wandering Trader, and Horses.
Some mobs can help you survive and beat the game wolfs, once tamed, can help you defeat mobs. Horses can help you travel to other places quickly. But to also defeat other bosses you need to kill dangerous mobs, for example to go to the end you need to kill blazes and get blaze rods which is one of the 3 recipes for crafting the eye of ender. To get a beacon you need to kill wither skeletons, get three skulls and get soul sand
When you start off you have to instantly start searching for wood to craft tools/other materials the first essential tool that you need to craft/create is the crafting table, without it you can't craft materials that you will need to reach the games biggest goal defeating the ender dragon! It takes time to complete the game of Minecrat.
Once you craft tools you can use them to get materials (ex:A pickaxe can be useined to get cobblestone and coal, an axe can be used to get more wood quickly, a shovel can be used to get sand and dirt, with sand you can craft glass, with a hoe (diamond, iron, gold, stone, wooden) you can fertilize grass and grow fruits, and with a sword you can defend yourself from mobs and other dangerous creatures) collecting materials isnt always easy, for example to get iron or diamons or gold; for iron you need a stone pickaxe, for diamonds you need to use either iron/gold and for gold you need to use either diamond/gold/iron.
Even if you have the materials to get other materials you still need to find them, for example diamonds aren't common they're very rare and usually found next to lava, gold isn't rare but it isn't too common, iron is pretty common so you shouldn't have trouble finding it. There's a lot of useful materials in Minecraft that are essential to completing the game.