I'll see what I can do to help you:
1. Go to your desktop and right click, there will be many options to choose from, go to New-> Compressed folder and rename it.
2. Now, go to OS (C:)-> Feral Heart-> Media-> Terrains. You'll see a folder with the name of your map, go into it and select all the files in it, or go back and select the folder. (Whichever works)
3. Go back to your desktop and find your compressed folder, paste all the files, or the folder, into it.
4. You should have a mediafire account, if not quickly register. Once logged on, go to 'My Files', unless your already there. On the left side of the screen there will be a Upload button, click it then find your compressed folder in the desktop section.
As for the difference between general and local chat, when your using general chat, everyone in the map can see what your saying, when you use local only the people around you can see what your saying.