If your server is Private use the * labeled numbers instead of the ^ labeled numbers and vise versa (the rest you use)
1. Download the map.
2. Download the Minecraft-server.zip (on the server list on the main site).
3. Unzip the server to a place of your desire.
4. Put the downloaded map in the same folder as the server.
5. Rename it to server_level.dat (if it isn't already).
6. Set server.properties to make your server private (make public=true to public=false if you want to play privately and you may need to set verify-names to false).
7. Run start server.bat.
*8. Look in externalurl.txt and find your server address then copy it.
*9. Paste it in your browser address bar.
^10. Go to the server list.
^11. Look for your server and click on it.
12. Wait for it to load and then play!
If it doesn't work, open terminal, navigate to the directory you have minecraft-server.jar in and type
java -jar minecraft-server.jar
Then take a screenshot to show people the errors you're getting.
For navigating directories in terminal, you will start in your home folder. Type "cd foldername" to go into a folder of that name. If it has a space in the name, use a \ before each space. Type "cd ../" to back out of a folder.
Edit: Oh, you should also stick a "\" before any special characters like "!".