Start by logging into your Visma e-conomic account. Navigate to the data or reports section, and use the built-in export feature to download your data. Typically, you can export data in formats like CSV or Excel, which are commonly supported.

Once the data is exported, open the CSV or Excel file to ensure it is structured correctly. Remove any unnecessary columns or rows and correct any data inconsistencies. This is crucial for ensuring the data can be imported smoothly into DuckDB.

If you haven't already, download and install DuckDB from its official website (https://duckdb.org/). DuckDB is available for various operating systems, so choose the version that suits your system. Follow the installation instructions provided on the website.

Open a terminal or command prompt, and launch DuckDB by typing `duckdb` followed by the name you wish to give to your database (e.g., `duckdb mydatabase.db`). This command will create a new database file or open an existing one.

In the DuckDB shell, create a table that matches the structure of your exported data. Use the `CREATE TABLE` SQL command. For example:
```sql
CREATE TABLE my_table (
column1_name TYPE,
column2_name TYPE,
...
);
```
Replace `column1_name`, `TYPE`, etc., with the actual column names and data types from your exported data.

Use the `COPY` command to import your CSV or Excel data into the newly created table in DuckDB. For a CSV file, the command looks like this:
```sql
COPY my_table FROM 'path/to/your/exported_file.csv' (FORMAT CSV, HEADER TRUE);
```
This command tells DuckDB to read the CSV file and import it into `my_table`. Ensure the file path is correct and accessible.

After importing, verify the data integrity by running SQL queries in DuckDB to check for any discrepancies or errors. For example, run:
```sql
SELECT COUNT(*) FROM my_table;
```
Compare this count with the original data count to ensure all records were imported successfully. Also, inspect a few records to ensure data accuracy.

By following these steps, you can efficiently move your data from Visma e-conomic to DuckDB without relying on any third-party connectors or integrations.