I am having trouble installing them. I download them. I then copy them and paste them where it says too, in scenarios. I then do the thing with the Scenarios where it shows up in the choice box when you start playing. It says that it can't open the new scenario or something.
Any help would be greatly appreciated 
The following are the steps that I do, which work:
1. Make sure that the scenario is in its own separate folder under the folder "scenarios" (e.g., the 2004 scenario is in "scenarios/2004/").
2. Open "scenarios.p4e" in the scenarios directory and add a line that reads "
folderName/", where
folderName is the name of the above folder. Note that the order of the scenarios in this file is the order they show up in when you go to choose a scenario.
3. Open President Forever and start a new game; the scenario should now be listed and openable when you go to change the scenario.
