Part 2
Making new scenario folder

All scenario folders are located in \data\scenarios\ folder.
First thing that must be done is to secure game files from our changes.
Copy one of the scenario folders and paste it in the \data\scenarios\ folder, after that change the name of the folder to the one that fits your choice (example: My_Scenario).

Now the game still doesn't see your new scenario folder, because settings are pointing into another folder. To make the new scenario active go the \data\scenarios\My_Scenario folder and open misc.csv file *.
In column J under Scenario directory name you have to change entry to the new one, so change it to My_Scenario now.

As we are already here it's good to change the starting date of the scenario. For this are columns A, B and C. Those are impuls no, month and year. Please note that by default each month has got four impulses.

Important NOTE (by cpdeyoung):
American Excel users will notice that the csv files, "comma separated values", are actually semicolon separated values, per our European friends. I recommend using a text editor to replace all ";" with "," before opening in an American version of Excel. After your changes replace the "," with ";" for the game.