Within the Manual you have a Turtorialscenario. The Turtorialscenario can be played by the Peg Original Installer.
Please start the Peoples General 1.o exe to play the turtorial
The Mods has the same rules as the original installer. But there are some differences. For Exemple, Tanks in the Napoleonic mod are Horses. Its the same for other mods around this timeperiode.
Some campaigns are very hard or almost unplayable. To win them sometimes is the only way to modify a savegamevia Peg suite. You can make your units stronger or clone them to have more units. You can also bring your units near to the victory hex or remove some enemys.
Here you can download the tool : Peg-suite