qmk_firmware/data/templates/base/keymaps/default/keymap.c

// Copyright %(YEAR)s %(YOUR_NAME)s (@%(USER_NAME)s)
// SPDX-License-Identifier: GPL-2.0-or-later

#include QMK_KEYBOARD_H

// Defines names for use in layer keycodes and the keymap
enum layer_names {
    _BASE,
    _FN
};

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
    /* Base */
    [_BASE] = LAYOUT(
        KC_A,    KC_1,    MO(_FN),
            KC_TAB,   KC_SPC
    ),
    [_FN] = LAYOUT(
        _______, _______,  _______,
            RESET,    XXXXXXX
    )
};