without further information, it is hard to help
I am not a facebook user and will never be so I don't know what specs they require but a I did a quick search and here are their specs
http://en-gb.facebook.com/help/218673814818907
I have been a GoPro user for years and there is no problem uploading the .mp4 file
but you need to give us more info. Are you going to "split" your clips into smaller sections, what software do you have, which computer , what OS, how long do you want your clips to be, do you wish to change your resolution before uploading, what resolution did you set your GoPro to, do you want to reduce it
I may have more questions
bob