Ensure you have access to both the Postgres database and the Typesense server. You need to have the necessary permissions to read data from Postgres and to write data to Typesense. Install any required tools like `psql` for accessing Postgres and `curl` or any HTTP client for interacting with Typesense.

Use SQL queries to extract the data you need from your Postgres database. You can use `psql` or any other SQL client to run your queries. Export the results to a CSV or JSON file format, depending on your preference. For example:
```bash
psql -U username -d database_name -c "COPY (SELECT FROM your_table) TO STDOUT WITH CSV HEADER" > data.csv
```
Replace `username`, `database_name`, and `your_table` with your actual PostgreSQL credentials and table name.

Transform the extracted data into a format that Typesense can accept, typically JSON. If you exported to CSV, you might need to write a script in Python or another language that reads the CSV and outputs JSON. Ensure that the JSON structure matches the schema you plan to use in Typesense.

Before importing data, define a schema in Typesense that corresponds to your data structure. This involves specifying fields, their types, and any unique constraints. You can create a collection in Typesense using an API request:
```bash
curl -X POST "http://localhost:8108/collections" \
-H "X-TYPESENSE-API-KEY: your_api_key" \
-H "Content-Type: application/json" \
-d '{
"name": "your_collection",
"fields": [
{"name": "field1", "type": "string"},
{"name": "field2", "type": "int32"},
// Add other fields as necessary
]
}'
```

Split your JSON data into chunks if necessary to avoid exceeding memory or API limits. Typesense recommends batch importing data for efficiency, so group your data into manageable sizes.

Use the Typesense API to import your JSON data. You can do this using `curl` or another HTTP client. Make sure to loop through each JSON chunk if you split your data:
```bash
curl -X POST "http://localhost:8108/collections/your_collection/documents/import" \
-H "X-TYPESENSE-API-KEY: your_api_key" \
-H "Content-Type: application/json" \
--data-binary @data.json # Adjust to send your JSON data
```

After importing, verify that the data in Typesense matches the original data in Postgres. You can query the Typesense collection and compare results with the original dataset to ensure data integrity. This step ensures that no data was lost or corrupted during the transfer process.

By following these steps, you can manually migrate data from a Postgres database to a Typesense collection without relying on third-party connectors or integrations.