Hi
I would suggest you go to Tools>Import from the dashboard and then on the bottom of the page there is an option to clear the mappings.
https://s3-eu-west-1.amazonaws.com/uploads-eu.hipchat.com/36185/2368368/6PbcHW4FmC5LskG/upload.png
Once you clear the mappings then the system should force you to map each column which should then hopefully help you import.
All you need is Date / Description/ Amount or Money in and Money out columns on your csv file to import.
If you still have a problem please make use of the guide below which has a video taking you step by step which is very helpful and clear.
https://www.clearbooks.co.uk/support/guides/video/how-to-import-a-bank-statement/
Best regards
Latha