Hi,
If you are not sure about the procedures, I have seen map packs being sold on eBay for a small amount of money that should come with all the instructions.
2017.Q4 is the latest edition of maps so far, Naviextras seems to be on a half-year update cycle.
To go in to the test mode with the newer firmware you need a new file with a fruity name. The patch installation should then proceed as described in the original archive you got. For all the operations you need to use USB1 port of the headunit.
To install the new maps you need additional copy script files. First you copy