Hi.
Welcome!
Fantasy Grounds can be a little frustrating at first but it becomes pretty intuitive once you use it a bit.
To bring up your Fantasy Grounds data directory you can click the folder icon on the Fantasy Grounds launcher.
The modules will go into the module directory, this is true for everything with a .mod extension. Once it is in the modules directory you can load it from the library button by clicking the modules button and loading the newly added module.
In the event you run across an .ext that would go in the extensions directory. This is not important here but is useful to know.
If you load your campaign up and click on the images button there is another folder icon. This will open a folder directly to the images directory. Fantasy Grounds will see images placed in this directory (or subdirectories) and automatically add them to the new dropdown or whatever dropdown you happen to have focus on when you clicked the folder icon. It is helpful in locating your images to not be in a random dropdown when adding images.
Once you have your image you can drag and drop the associated link into the notes section of the system that you want to associate it with along with any additional text you want to add.
If you want players to be able to see the image you need to also share the image otherwise they will see the link tab but it will not be viewable.
If you are looking for systems in the Trojan Reaches the main stats are all in the Trojan Reaches module located
here. I am not able to share text or graphics with the modules but the system UWP and associated information gives a good head start.
Hope this helps.