You need to read the manual and learn how to do a simple update query using an UPDATE statement in your SQL query.
This will allow you to update the text. I am not going to explain how to do this as this is very very simple and you can pick it up from the manual. Info for the mysql() functions can be found here...
http://www.php.net/manual/en/ref.mysql.php
Loading your files can be done in at least two ways. First with FTP. PHP has built in FTP functions that allow you to connect to and load/download files, traverse the directory structure, rename files etc. Info on PHP's FTP functions can be found at ...
http://www.php.net/manual/en/ref.ftp.php
The other way to load your files is via HTTP, or through an HTML form. This way, you do not have to create an FTP script. Either way is not difficult. For this method to work, you will need to make sure the proper permissions are set on the directories you are loading to. Info on loading files via HTTP can be found here...
http://www.php.net/manual/en/features.file-upload.php
Get started on your script and post what you come up with along with information about what you are trying to do with a particular piece of code and myself or someone else will gladly help you. I am not going to write it for you though.