Good work Imp, impressive feedback too!
Right, here comes the tricky part:
1)Unzip the files.
2)Install the txt files into your campaign folder.
3)Install the scenario files spscn427.cmt and spscen427.dat into your
scenario folder (not the campaign folder).
4) Start the game.
5) Add scenario 427 (The Best 02: At Tur II) to slot 002 of Campaign 018. You do this by entering the Edit Campaign function.
6) Save (in the lower right hand corner of the Edit Campaign screen you'll find the save button. Click it when the new scenario has been added).
7) Save again.
8) Go back to your saved game and contine from there. The new txt files should appear along with the next battle.
Post here if you (or anybody else) has any questions.