To upload a video, you must first be logged into to Dotsub. Once you are logged in, look to the right and click on the site menu. From here you will see 'Post a new video'.
Fill out the meta-data information page, be sure to click the "make this video public" box if you would like to have your video public. Hit the browse button, and select the video from your desktop and hit the "upload" button at the bottom of the meta-data page. Please be aware that it does take time to upload. Longer videos will take longer to upload. You will receive a confirmation e-mail from Dotsub once you video has been processed.
You can also upload a .flv file from an existing Internet address by clicking o the blue "Create From Existing Internet Address" tab just next to the "upload" tab. Enter the url and hit the 'upload' button.