FTP is an acronym for File Transfer Protocol.
It is best described as a method in which to transfer files from one place to another over TCP/IP ( the Internet, an internet, or an intranet).
It is a cousin to HTTP or HyperText Transfer Protocol (How you get your web pages)
Under most circumstances you would need an FTP program. There are many free ones out there and I am sure someone will mention one or two.
If you run WinXP you are in luck. Internet Explorer 6.0 and higher supports FTP right in the browser - not the greatest but works if you do not FTP often.
It is just a matter of typing in the right stuff.
For opening a webpage you would use (example): http://www.somewhere.com/
For FTP it isn't much different. You need to change the HTTP to FTP and add a username (if required).
Note the lack of www --- that is usually not needed.
Once you type in the above, a window asking for a password will appear and then you can browse the folders as if you were on your own machine.
Now, this is assuming that you were given a username and password. Many places have an anonymous area where a general username and password (example user:"Guest" pass:"") work and it is usually an upload area.
Now that the lesson is over, are you trying to direct FTP to OFPEC?
Because I do not believe they allow that. If you are trying to submit a mission, or set of scripts, or something.. there are many pages that you can use to do so. Check your menu bar for the word "submit..." on any of the menu items in the area of interest.