The Galleria theme comes with some great video options for your home page.  Let's take a look at these options in more detail.  There are two types of play options for your video.

Autoplay

With this option enabled, your video will automatically play in the background as your customer visits the page.  This can be situated as the first section on your home page and configured in full width and/or height to create a hero video effect, or you can place some text and button next to it (as shown below) for content further down the page.  When the video is the first section, it will be stretched to fill in the height you specify and will play without audio, so you will want to choose a more cinematic video where sound isn't important.  Check out mediaBOOM for some inspiration.  In this scenario, you can also overlay your header and navigation on top of it by enabling the Overlap header content option in your Header section settings.  Optionally, you can overlay a play button over autoplayed videos to open the video with sound in a popup window.

Play on click

With this option, you may select a background image as a preview for your video.  The text you enter will appear centered vertically and horizontally on the image along with a play button.  When the play button is clicked, the video will play right in a popup window with sound and all the controls you would expect from a video on YouTube or Vimeo.  This is a great way to showcase your brand, products, promotions, or whatever you want!