Hey xphp:
Welcome to the forum.
Well, I don't know a lot about MYSQL either, but we all have to learn sometime, so hang in there and I am sure you will catch on sooner or later.
First of all sometimes it helps us answer you question if you state what version of MYSQL you are using and what you are using for a server (Windows IIS or Apache, etc.. I guess that really isn't necessary in this particular case, but just thought i would mention it.
About your code.
This code is creating a database table called "shoutbox". There must have been some code before this that created the database.
The code after the CREATE TABLE shoutbox is creating the fields in the database table, Id, ip, name, url, message, date, Primary Key. These are all fields within the table.
If you entered this code from the command prompt then you can check and see if the database table and fields got created by (at the MySQL Command Prompt) first type: Use database; (where database is the name of this particular database).
Then, at the command prompt, you can type: Describe database; (again, use what ever the name of the database is) and you should see a list of all the fields (Id, ip, name, url, message, date, Primary Key) that were created by the code in your posting. If you don't see them then you know that they did not get created, most likely because there is something wrong with your code.
In your code you have <br/> and that should either be eliminated or changed to <br>. You can try leaving it out and see what happens or putting it in and seeing what happens. It is suppose to create a line break in regular HTML, but I have never used it when creating database tables.
So, if you ended up with a database (whatever it was named) and when you did the: Describe database; you saw all of the fields got created you could now enter data into that database.
You can do this at the command prompt or by writing PHP code.
I would suggest you read up on using the Insert statement either in the MYSQL manual or a book, if you have one. That would be the next step to get data into your database.
After you get some data into your database then you should probable read about how to query your database.
You might take a look at some of the tutorial at: http://www.w3schools.com/ for PHP tutorials. Just go to that Web site and then look down the left hand side until you come to PHP.
Also, read some of the MYSQL manual at: http://dev.mysql.com/doc/administrator/en/index.html
Just keep reading and writing code and you will catch on before you know it.
I hope this helped you a little bit.
Good Luck