Begin by examining the structure of your JSON file. JSON files can vary greatly in complexity, so understanding whether your data is flat (simple key-value pairs) or nested (keys with arrays or objects as values) is crucial. This will inform your approach to parsing and how you map JSON keys to CSV columns.

Use Python, which has built-in libraries to handle both JSON and CSV files. Ensure you have Python installed on your system. You can check by running `python --version` in your command line or terminal. If not installed, download it from the official Python website and follow the installation instructions.

Use Python's `json` module to read the JSON file. Open your JSON file in read mode and load the data using `json.load()`:

```python
import json

with open('data.json', 'r') as json_file:
data = json.load(json_file)
```

This code reads the contents of `data.json` into a Python dictionary or list, depending on the structure.

Determine the columns you need in your CSV file. If your JSON data is nested, you'll need to flatten it. Decide the column headers based on the keys in your JSON data. For example, if you have nested data, you might use dot notation like `user.name`.

Use Python's `csv` module to write the data into a CSV file. Open a new CSV file in write mode and use `csv.DictWriter` to map your JSON data:

```python
import csv

with open('output.csv', 'w', newline='') as csv_file:
csv_writer = csv.DictWriter(csv_file, fieldnames=[list of your column headers])
csv_writer.writeheader()
for entry in data:
# Flatten nested JSON if needed
csv_writer.writerow(entry)
```

Adjust the `entry` variable to match your desired CSV structure. For nested JSON, transform each entry into a flat dictionary.

If your JSON file contains nested structures, you need to flatten them before writing to CSV. Create a helper function to recursively parse nested dictionaries or lists into a flat structure. For instance:

```python
def flatten_json(y):
out = {}

def flatten(x, name=''):
if type(x) is dict:
for a in x:
flatten(x[a], name + a + '_')
elif type(x) is list:
for i, a in enumerate(x):
flatten(a, name + str(i) + '_')
else:
out[name[:-1]] = x

flatten(y)
return out
```

Use this function to process each JSON entry before writing to CSV.

After writing the data, open the CSV file to verify that all data has been correctly transferred and formatted. Check that all fields are present and that nested data has been appropriately flattened. Make adjustments if necessary by revisiting previous steps.

By following these steps, you can effectively move data from a JSON file to a CSV file using only Python's built-in capabilities, without relying on third-party connectors or integrations.