As wire story structure differs by suppliers, product and type, it's obvious that you cannot start to write the XSLT for import workflow without analyzing the input content first.

For this, you need sample files or feeds.

Some samples are available here:

Example 1: AFP XML format

Example 2: Bloomberg XML format

Example 3: Reuters text format

Example 4: EFE text format

Then you need to find out about the attributes matching - to which attribute in the original content corresponds which GN4 attribute. Typically, the original content may contain metadata you won't use in GN4.

Done that, you can start to write your XSLT (explained step-by-step in the above listed examples).