Extract sales order document in excel prepared for printing to structured table

Hi all, this question may be a complicated one, and I'm just looking for an idea about where to start:

I have an excel file exported from our old ERP system. The file contains the data of thousands of sales orders. Each sales order contain a order header and order lines (lines may contain 1 or more items).

These data are layed out in a way that is prepared for printing the document, and my job is to convert the data to two structured table (one table for headers, one table for lines).

The original data (sensitive data blurred):

Example of target format:

What function do you think can help me with this task? Any idea will be appreciated, thanks!