Hello anchorman,

  To transfer your data from Online to Desktop you can also use one of the apps that are designed for this matter. You can get an application and export all the data you have got within your Online company using for example Business Importer app. And then import that data by using Business Importer for Desktop app. 

  That will be a very convenient solution, as both apps have an intuitve interface, lot of guides and support teams that will be glad to help you with the matter. However, the minus here is that most likely you will have to purchase both apps as in the free trial mode they can proceed only limited amount of lines.

  Still, if time is more precise here than a bunch of manual entries - those apps will do a great job.