2. Install [DFU-Programmer][dfu-prog] (the -win one).
3. Start DFU bootloader on the chip first time you will see 'Found New Hardware Wizard' to install driver. If you install device driver properly you can find chip name like 'ATmega32U4' under 'LibUSB-Win32 Devices' tree on 'Device Manager'. If not you will need to update its driver on 'Device Manager' to the `dfu-programmer` driver.
1. Install [CrossPack](http://www.obdev.at/products/crosspack/index.html) or install Xcode from the App Store and install the Command Line Tools from `Xcode->Preferences->Downloads`.
Unlike the other keymaps, prefixing the keycodes with `KC_` is required. A full list of the keycodes is available [here](https://github.com/jackhumbert/tmk_keyboard/blob/master/doc/keycode.txt). For the keycodes available only in the extended keymap, see this [header file](https://github.com/jackhumbert/tmk_keyboard/blob/master/keyboard/planck/keymap_common.h).
The extended keymap extends the number of function layers from 32 to the near-infinite value of 256. Rather than using `FN<num>` notation (still available, but limited to `FN0`-`FN31`), you can use the `FUNC(<num>)` notation. `F(<num>)` is a shortcut for this.
The function actions are unchanged, and you can see the full list of them [here](https://github.com/jackhumbert/tmk_keyboard/blob/master/common/action_code.h). They are explained in detail [here](https://github.com/jackhumbert/tmk_keyboard/blob/master/doc/keymap.md#2-action).
Macros have been setup in the `keymaps/keymap_default.c` file so that you can use `M(<num>)` to access a macro in the `action_get_macro` section on your keymap. The switch/case structure you see here is required, and is setup for `M(0)` - you'll need to copy and paste the code to look like this (e.g. to support `M(3)`):
`MACRODOWN()` is a shortcut for `(record->event.pressed ? MACRO(__VA_ARGS__) : MACRO_NONE)` which tells the macro to execute when the key is pressed. Without this, the macro will be executed on both the down and up stroke.