What does it mean?

So, lets point out the main parts that'll be of interest to you:

1. Thumbnail - This is the poster frame - a quick reminder what this video is about.  You can select these items (click on anywhere that isn't text) and press Space to QuickLook.
   
2. Title - As well as being your summary of the video, it's used to generate the URL that other people see (this means you get URLs that make some sense, and read nice too!).  To make changes, click on the title and type in what you'd like. The changes are made automatically (there's no "Apply" button).  Note that if you update the title after you've published a video, it's URL will change!
3. Description - A space for you to use more words to explain what your video is all about.
4. Close, link and options buttons - The ciose button will remove the item from the list. It isn't remove from your computer, just removed from this list. If the item is published, you will be prompted to un-publish it first. You cannot remove items from the list that are already published.  The link and options buttons are explained later.
   
5. Publish - Where all the magic happens. Push this to get your stuff onto the web.  This button changes to reflect what you can do with the media at any time. For example: If your media is already published, this button will be labelled "Unpublish", and allow you to remove the media from the web.
   

The Toolbar

1. Add Movies - Lets you add additional movies to be published.
2. Resync - Synchronizes the server's idea of what is published (including titles & descriptions) with what you have on your machine. The information is versioned, so if you update your titles/description (or even add more videos) on another machine, you can sync up and have the latest info on your current machine at any time.
3. View on Web - Takes you to the index page for your videos. 
4. Buy Credit - Takes you to the shinywhitebox store where you can purchase hosting credit. Note that you can also setup your account to automatically top up (see below).

The bar underneath the toolbar lets you filter the items and sort them how you like.  The first group (All | Published | Unpublished | Missing) lets you filter the list to show just those items you're interested in.  The second lets you sort in ascending or descending order.