1. Download MTA
here.
2. Install it.
3. Open it.
4. Click on the "Map Editor".
5. Watch the tutorial, or skip it.
6. Find a location where do you want to start building map.
5. Click on "Objects" box, find an object you wanna use.
6. Move the objects using arrow keys, shift + arrow keys = move objects faster
7. Rotate objects, using CTRL + Arrow keys or CTRL + Page up & Page Down
8. When you finish with the objects, save the map. (It's in the upper boxes menu)
9. Your map is now located in MTA Directory/server/mods/deathmatch/resources/MAP NAME FOLDER/Here is the .map file.
10. Now open it using text editor and copy everything what's in it.
11. Go to
http://www.convertffs.com/ and paste the code you copied here.Click "convert".
12. Wait a bit. The code should show up.Select it all and copy it.
13. Paste the objects code under "OnGameModeInIt" in your gamemode or filterscript.
Hope that helped.
NOTE: I copied and edited that a bit from other forum, yea I posted it there as well.