Log into your EmailOctopus account by navigating to the EmailOctopus website and entering your login credentials. Ensure you have the necessary permissions to access the data you wish to export.

Once logged in, navigate to the section of your account where the data is stored. This could be lists, campaigns, or reports. Identify the specific dataset you wish to export, ensuring you have full access to all the data fields you need.

EmailOctopus typically provides an option to export data in CSV format. Find the export option, often available in the list or data management sections. Select CSV as the export format and initiate the export process. Save the CSV file to a known location on your computer.

Open the exported CSV file using a spreadsheet application like Microsoft Excel or Google Sheets. Review the data to ensure it is complete and formatted correctly. Make any necessary adjustments, such as correcting column headers or data types, to prepare it for JSON conversion.

Use a programming language like Python to convert the CSV to JSON. Create a Python script to read the CSV file and write its contents to a JSON file. Use Python libraries like `csv` and `json` to facilitate this process.

```python
import csv
import json

csv_file_path = 'path/to/your/exported.csv'
json_file_path = 'path/to/your/data.json'

data = []

with open(csv_file_path, mode='r', encoding='utf-8') as csv_file:
csv_reader = csv.DictReader(csv_file)
for row in csv_reader:
data.append(row)

with open(json_file_path, mode='w', encoding='utf-8') as json_file:
json.dump(data, json_file, indent=4)
```

Execute the script using a Python environment on your computer. Ensure any dependencies, such as Python itself, are installed. This script will read the CSV file and output a JSON file at the specified location. Check the JSON file for accuracy and completeness.

Open the generated JSON file using a text editor or JSON viewer. Verify the data structure and contents to ensure everything has been converted correctly. Once confirmed, the JSON file is ready for local use or further processing as needed.

By following these steps, you can manually export data from EmailOctopus and convert it into a JSON format without the need for third-party connectors.