Before you try and join a server you should do some research. Some servers require you to be on their white list before you can join their server, others allow anyone to join but only people on there white list are able to edit the world (Place/Destroy blocks). There are also servers which have no kind of white list but it is recommended to play on a server with a white list as it reduces the chance of people Griefing (Destroying other peoples work, setting the world on fire, etc) your creations. You should also find out the rules of a server before joining it, they are generaly listed on the servers website.

You can find a list of servers from various websites like the following:

When you click on "Multiplayer" on the main menu you will be brought to the screen which lists the servers you have bookmarked.

Click on "Add Server". Enter "Crazy Fools" as the server name and "" as the server address. After you have clicked on Ok, Crazy Fools will be listed and it will show if the server is currently running as well as how meny people are on it. To join the server click on it and then press the "Join Server" button (Note that if the server is down or if it is full you will not be able to join it).

You can also directly connect to a server by clicking on the "Direct Connect" button and entering the servers address. When you use this method it will not add the server to your server list.