Dynamic data - Export area

Hi, please check the attached document.
the story is the following.

Consider that this is a template, where a user clicking the "export" button can create a clean excel document with the values appearing in that area, comprised between A8 and A14 and C8 and C14

• The column "A", contains numbers that will be used as ID when exporting.

• If a user insert another line, the column must increase automatically and always give increasing values

• the data to export are the lines with an ID and having A, B and C, so in case there are more lines, these should be exported as well

How to achieve this?