Improvements to documentation (#1919)

* Typo: Github => GitHub

* Typo: windows => Windows, docker => Docker, and some punctuations

* "QMK Introduction" links to the right file

* "Unix" rather than "UNIX", which is a trademark

* Directory name is "keyboards", not "keyboard"

* "handwired" is a subdirectory of "keyboards"

* Punctuation and minor fixes

* macOS rather than Mac

* Punctuation and other minor fixes

* Vagrant Guide links to an existing file

* Jun Wako referenced with his name rather than his nickname

* Saxon genitive 's outside the link

1 files changed, 47 insertions, 0 deletions

diff --git a/docs/getting_started_introduction.md b/docs/getting_started_introduction.md
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+# Introduction
+
+This page attempts to explain the basic information you need to know to work with the QMK project. It assumes that you are familiar with navigating a Unix shell, but does not assume you are familiar with C or with compiling using make.
+
+## Basic QMK structure
+
+QMK is a fork of [Jun Wako](https://github.com/tmk)'s [tmk_keyboard](https://github.com/tmk/tmk_keyboard) project. The original TMK code, with modifications, can be found in the `tmk` folder. The QMK additions to the project may be found in the `quantum` folder. Keyboard projects may be found in the `handwired` and `keyboard` folders.
+
+### Keyboard project structure
+
+Within the folder `keyboards` and its subfolder `handwired` is a directory for each keyboard project, for example `qmk_firmware/keyboards/clueboard`. Within it you'll find the following structure:
+
+* `keymaps/`: Different keymaps that can be built
+* `rules.mk`: The file that sets the default "make" options. Do not edit this file directly, instead use a keymap specific `Makefile`
+* `config.h`: The file that sets the default compile time options. Do not edit this file directly, instead use a keymap specific `config.h`.
+
+### Keymap structure
+
+In every keymap folder, the following files may be found. Only `keymap.c` is required, and if the rest of the files are not found the default options will be chosen.
+
+* `config.h`: the options to configure your keymap
+* `keymap.c`: all of your keymap code, required
+* `rules.mk`: the features of QMK that are enabled
+* `readme.md`: a description of your keymap, how others might use it, and explanations of features. Please upload images to a service like imgur.
+
+# The `config.h` file
+
+There are 2 `config.h` locations:
+
+* keyboard (`/keyboards/<keyboard>/config.h`)
+* keymap (`/keyboards/<keyboard>/keymaps/<keymap>/config.h`)
+
+If the keymap `config.h` exists, that file is included by the build system and the keyboard `config.h` is not included. If you wish to override settings in your keymap's `config.h` you will need to include some glue code:
+
+```
+#ifndef CONFIG_USER_H
+#define CONFIG_USER_H
+
+#include "../../config.h"
+```
+
+If you want to override a setting from the parent `config.h` file, you need to `#undef` and then `#define` the setting again, like this:
+
+```c
+#undef MY_SETTING
+#define MY_SETTING 4
+```