When you upload a CSV file to NetSuite that follows a format similar to a sample previously created within the NetSuite system, NetSuite employs an automatic matching process. This process involves comparing the data fields in your uploaded file, particularly focusing on identifiers like memo entries or other specified criteria, with existing records already stored in NetSuite. By doing so, NetSuite facilitates the seamless integration and synchronization of external data with its internal database, ensuring that new information aligns accurately with pre-existing data points. This functionality not only streamlines data management processes but also enhances accuracy and consistency across your NetSuite platform, thereby supporting efficient and reliable business operations
The Picture shown below specifies the number of transactions automatched .

The picture below shows the one which is matched automatically in the review section of match bank data
Navigation: Transactions -> Bank -> Match Bank Data
Select the coressponding account which you inported earlier.
