If you see a screen like this:
this means that the video is processing, which is completely normal. The amount of processing time may be dependent on the size of the file.
Once Submit uploads a video to Google Drive, Google does some processing on their end to make the video available for streaming. While this is occurring, you'll see a message that says "We're processing this video. Please check back later." After the video is processed (it usually takes just a few minutes), a video thumbnail will replace that message.
You can wait for the videos to finish processing to stream them directly in your browser. Or, you can download them to view before they have finished processing.