Before you submit your final video for rendering, there is the option to ‘Email me when previews are ready’ to allow you to check over your video and amend it.
However, if your video has been returned to you and you would like to edit the content, here is how:
Step 1: Navigate to 'my videos' and find the video you wish to edit. Click 'play video'. Step 2: Click the blue button on the right hand side of the video titled 'edit video'. Step 3: Use the pencil icons on the right hand side to make your edits. Step 4: Select audio. Are you using the same audio or something new? Step 5: Submit your video.