Hi Simon,
The file in its downloaded form can't be placed into RB without a bit of work so to import the routes you're going to improve your PC skills somewhat :)
First of all you'll need to download a free SQLite database editor to use. Seeing as you just need something simple for doing this I'd suggest that you downloaded a copy of SQLite Database Browser which is FREE and will do everything you need it to do whilst you learn SQL.
Once you've downloaded and placed a copy of it somewhere convenient you'll need to do the following.
1. Create 2 copies of the NavData.db3 database from the 'AirNav Radarbox 2009\Data' folder and place where you wish (keep one safe as a backup)
2. Start SQLite Database Browser and use the File - Open Database function to open one of your copies of NavData.db3
3. Now use File - Import - Import Table From CSV File. Browse to my file and import the data from it.
4. A new window will now open. In the New Table Name entry box enter Routes2. Tick the box for the option Extract field names from first line. Now click the Create button and wait until you receive confirmation that the process is complete. You should now have a new table in your database called Routes2 that contains my TCX route data.
5. Click on the Execute SQL tab and in the SQL String: box paste the following:
REPLACE INTO routes (FN,NO,ND,NV,CH)
SELECT FN,NO,ND,NV,CH
FROM routes2
and click the Execute Query button to perform the query above.
6. Now enter the following query in place of the last one and execute it to set your database back to its standard format:
DROP TABLE routes2
7. Now use File - Save Database to save the changes.
8. Copy your edited NavData database back into the \Data folder to overwrite the original.
9. Start up RB. If all starts okay you should now see the TCX flights getting populated with flight numbers (MyFlights only). If RB doesn't start copy the backup version of NavData back to restore the original.
VERY IMPORTANT - Make sure you make the 2 copies of NavData.db3 in step 1 - one to edit and the other as a backup just in case the process goes wrong (it shouldn't if you follow the instructions correctly!).
HTH