Often when you need to install a script on your server, the instructions require you to change Permissions on a file.  This may sound complicated but really is very simple.

Login to your site using the Filezilla “Client”.

Right click the file or directory that you want to change permissions on:

The following screen will appear:

On this screen you have two choices for changing permissions.  You can check the “Read”, “Write” and “Execute” check boxes, or you can type a Numeric Value into the “Numeric Box”.  This latter method is usually the one that you will use, since most instructions will say “Change permissions on the file or xxx” where xxx is a number e.g. 755, 666, 777 etc.  All oyu do is type the number into the box, and click OK. 

In the screen shot above, the file has its permissions set to 755.