Map contacts from one system to another with Excel

We have been using Harvest for our invoicing and now have to move over to a new system https://fakturownia.pl/.

We have an Excel of all our clients and need this mapping to the https://fakturownia.pl/ system using Excel.

There are only 230 clients need to be mapped to the new system, and if you are good at Excel this houldn't take too long to do - I am not good at Excel, hence the posting of the job!

Attached are examples of the Harvest export and a typical Fakturownia import so you can see what needs to be done!

The https://fakturownia.pl/ headers of the excel are in Polish as it's a Polish system, but I am sure you can use Google Translate to help you along the way!

All details from the old list need to be in the correct feilds for the new fakturownia list.

This is a very important project and needs to be submitted by us to the Polish Government.

Please contact me for the actual Excel examples as I can't uplod them here.