You must know the format of the ledger before importing.
To do so, go to tools-object designer-form
Select mapping, then run.
Again, select Open-Item.
You will see the field no, field name, Field caption.
Then u have to create your own data based on the description.
Once your data is ready, kindly select file name to browse your file.
When it is done, click button function, select import data.
Done.