Here are step-by-step instructions to migrate decks_v2.json to .dck files with the desired structure, assuming no prior knowledge of the command line:

1. Open a web browser and go to the following link: https://github.com/taw/magic-preconstructed-decks
2. Click the green “Code” button and select “Download ZIP” to download the repository as a ZIP file.
3. Extract the ZIP file to a folder on your computer.
4. Open the folder and create a new file migrate_decks.py.
5. Right-click on the file and select “Open With” and then choose a text editor such as Notepad or Sublime Text.
6. Copy the following Python script and paste it into the text editor:

import json
import os
import re

from typing import List, Dict

DECKS_FOLDER = 'Preconstructed Decks'

def load_decks(file_path: str) -> List[Dict]:
    with open(file_path, 'r') as f:
        return json.load(f)

def format_deck_name(name: str) -> str:
    name = name.lower().replace(' ', '_').replace('-', '_')
    return re.sub(r'[^a-z0-9_]', '', name)

def get_deck_info(deck: Dict) -> Dict:
    return {
        'name': format_deck_name(deck['name']),
        'type': deck['type'],
        'set_code': deck['set_code'].upper(),
        'set_name': deck['set_name'],
        'release_date': deck['release_date'],
        'deck_folder': DECKS_FOLDER,
        'cards': deck['cards'],
        'sideboard': deck['sideboard']
    }

def build_deck_text(deck_info: Dict) -> str:
    lines = [
        f'// {deck_info["name"]}',
        f'// Set: {deck_info["set_name"]} ({deck_info["set_code"]})',
        f'// Release Date: {deck_info["release_date"]}',
        '',
    ]

    for card in deck_info['cards']:
        lines.append(f'{card["count"]} [{card["set_code"]}:{card["number"]}] {card["name"]}')

    lines.append('')
    lines.append('SB:')

    for card in deck_info['sideboard']:
        lines.append(f'{card["count"]} [{card["set_code"]}:{card["number"]}] {card["name"]}')

    return '\n'.join(lines)

def build_deck_path(deck_info: Dict) -> str:
    return os.path.join(deck_info['deck_folder'],
                        deck_info['type'],
                        deck_info['set_code'])

def write_deck_file(deck_info: Dict, deck_text: str) -> None:
    deck_path = build_deck_path(deck_info)
    os.makedirs(deck_path, exist_ok=True)

    filename = f"{deck_info['name']}.dck"
    file_path = os.path.join(deck_path, filename)

    with open(file_path, 'w') as f:
        f.write(deck_text)

def migrate_decks(input_file: str, error_file: str) -> None:
    decks = load_decks(input_file)

    error_decks: List[Dict] = []
    for deck in decks:
        try:
            deck_info = get_deck_info(deck)
            deck_text = build_deck_text(deck_info)
            write_deck_file(deck_info, deck_text)
        except KeyError:
            error_decks.append(deck)

    if error_decks:
        with open(error_file, 'w') as f:
            json.dump(error_decks, f)

if __name__ == '__main__':
    migrate_decks('decks_v2.json', 'error_decks.json')

7. Open a terminal or command prompt on your computer. On Windows, you can do this by pressing the Windows key and typing “cmd” and then pressing Enter.
8. Navigate to the folder where the decks_v2.json file and the migrate_decks.py file are located. You can do this by typing cd followed by the path to the folder, such as cd C:\Users\YourName\Downloads\magic-preconstructed-decks-master.
9. Type python migrate_decks.py and press Enter to run the Python script.
10. Wait for the script to finish running. It will create a .dck file for each deck in the decks_v2.json file, with the desired structure.

Note: If you don’t have Python installed on your computer, you can download it from the official website: https://www.python.org/downloads/. Choose the latest version for your operating system and follow the installation instructions.