I've never uploaded a video to Facebook on my own account but for my Uncle on his account, to date I have uploaded 217 videos for him. He's one of those people who no matter how many times I show him or write out the instructions, he just can't seem to figure out himself, or don't try. No Matter. The curse of relatives. :-)
I'm assuming here you have a video on your system to upload to your account on Facebook and of course you have a Facebook account.
First a few notes.
So log into Facebook.
At the top of the page you'll see the option to Add Photos/Video. Clicking on that opens a box for you to find your videos on your hard drive.
Click on the video and then Open takes you back to Facebook and you'll see a thumbnail view in a box similar to here:
Where it is written Say something about this video.... just click there and say something about your video. Date, event, who's in it, reason for posting, whatever you want. You don't have to type anything. You can set the video for Public viewing or just friends by clicking on the button down by the blue Post button or just click on the blue Post button to upload it to Facebook. If you change your mind, before posting, you could move your cursor over the thumbnail view and a small white x appears in the corner. Clicking on that will remove it.
It's as simple as that. By the way this is the same procedure for uploading pictures as well. Just look for your pictures instead of videos.
Find your videos on Facebook.
Facebook doesn't make it obvious where to look for your videos. Click on your name across the top.
Click on Photos on your Timeline.
And then Albums.
And you should see there one labelled Videos - screen shot is from my Uncle's because I don't have any videos upload.
Anyway I hope this is useful to someone somewhere.