All of the scenarios in the Customized Scenario Database require you to download and install files. But if you can download and install game files that people send you to play - you can do this. The process is exactly the same.
There are four different file types which might be needed in order to fully open and play a customized scenario. Whichever files are needed to play the scenario you select will be included with the folder you download.
ORDER OF BATTLE FILES
The OOB file is necessary as it contains the Order of Battle for customized scenarios to work correctly. These end with the prefix .OOB.
The Scenario file is also necessary as it contains the code to make the scenario work. These end with the prefix .SCN.
The Map file is necessary as it provides the battleground for you to play on. These end with the prefix .MAP.
The Data file also contains information which the scenario will not be able to run without. These end with the prefix .PDT.
None of the files you download will interfere at all with any other standard files in your games, nor affect any ongoing games in any way.
Once you download the files from the Customized Scenario Database, you will then copy and paste the specific files you downloaded (using the same method you use for turns) into the correct folders of the specified game on your Computer.
As an example, below is shown the !Stonewall.OOB file being installed into the Campaign Gettysburg game.
Here is a second example. In this image the !!!Stonewall at Gettysburg.SCN file is being placed into the Scenarios folder of Campaign Gettysburg.
If you have any questions, feel free to email me at any time for assistance. You might also visit the excellent webpage maintained by Ken Miller which also discusses gaming files and how they work in greater detail. This page can be found at https://acwgc-engineering.com/.
Another valuable resource for assistance are your regular gaming partners. Many members have lots of experience downloading these types of files and can likely assist you if you need help.