Setting permissions / CHMOD
There are other pages here that explain why we need to set file permissions - this will just show you how to do it.
In a WordPress install, 2 files that you will probably want to alter are the index page, and the css which controls the layout. Here's how you change index.php - the process is the same for any file.
Right-click 'index.php' and select 'File Permissions'
A popup screen will appear.
Don't worry about the check boxes. Just delete the 'Numeric value:' and enter the number you need - in this case it's 666. Then click OK.
You can now see that the file permissions have been changed.
Folders can have their permissions changed in exactly the same manner.