I already suggested you do the tutorials and the help file to learn about the engine, because the engine is too much to "learn by doing".
That way you also might have learned about the sample maps included in the program...
There's the question you're asking and the question I think you want.
Yes, the map is stored in a file, you could download an entire map.
No, you generally do not find maps available to download. Maps are a huge part of what actually makes your game - what would be the point of you saying you made a game if your towns or dungeons or whatever are the same as someone else's?
Many tilesets that you purchase will include more sample maps so that you can see how to use the various pieces of that tileset well.
Aside from that, you're talking about hiring other people to draw your maps for you.
Haven't been on here actively in awhile, project is going strong my biggest issue is the STORY, i'm refining the plot and learning so much i decided to take a writers class to improve even more but the programming and functionality of the game is stepping up nicely!