There are two different modes you can play with on minecraft. One is creative, and one is survival. On creative mode, you are free to build anything easily. It is easy to get gold and diamond, unlike on survival mode. On creative mode you don't need to craft anything or chop down wood because you can get those stuff on crafting mode. You can use blocks to create your house. You can also fly on this mode.
But on survival mode your life is harder. The monsters will hurt you (on creative mode if you choose to have monsters in your world, they will not hurt you) on that mode. You cannot fly, unlike how you can on creative mode. You craft stuff to make blocks, furniture, doors, fences, etc. It is harder to build houses on survival mode. You have to try to defeat monsters and mine for iron, diamond, or gold. The easiest option is to chop down wood and try to make blocks and doors out of those blocks. If you need light you can use a torch. But, you can also use a potion of night vision. Although it's harder to make potions.
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