For the full Quantum feature list, see the parent readme.md.
Download or clone the whole firmware and navigate to the keyboards/cluecard folder. Once your dev env is setup, you'll be able to type make to generate your .hex - you can then use the Teensy Loader to program your .hex file.
Depending on which keymap you would like to use, you will have to compile slightly differently.
To build with the default keymap, simply run make default.
Several version of keymap are available in advance but you are recommended to define your favorite layout yourself. To define your own keymap create a folder with the name of your keymap in the keymaps folder, and see keymap documentation (you can find in top readme.md) and existant keymap files.
To build the firmware binary hex file with a keymap just do make with a keymap like this:
$ make [default|jack|<name>]
Keymaps follow the format keymap.c and are stored in folders in the keymaps folder, eg keymaps/my_keymap/