page.json

{
    "title": "Change Option + Up / Down to Page Up / Down  P",
    "rules": [
        {
            "description": "Change Option + Up / Down to Page Up / Down",
            "manipulators": [
                {
                    "from": {
                        "key_code": "down_arrow",
                        "modifiers": {
                            "mandatory": [
                                "left_option"
                            ],
                            "optional": [
                                "any"
                            ]
                        }
                    },
                    "to": [
                        {
                            "key_code": "page_down"
                        }
                    ],
                    "type": "basic"
                },
                {
                    "from": {
                        "key_code": "up_arrow",
                        "modifiers": {
                            "mandatory": [
                                "left_option"
                            ],
                            "optional": [
                                "any"
                            ]
                        }
                    },
                    "to": [
                        {
                            "key_code": "page_up"
                        }
                    ],
                    "type": "basic"
                }
            ]
        }
    ]
}

karabiner://karabiner/assets/complex_modifications/import?url="https%3A%2F%2Fgist.github.com%2Fpedrospdc%2F4b994594258d83055a815bbdb7a87cdc%2Fraw%2F777da1dc31f79c21c6912a69294c31a338fa259e%2Fpage.json