Thanks for reaching out, and thanks for using Swifty WordPress theme along with BoldGrid Post and Page Builder!
In order to change the video on a webpage you need to find the page you want to edit and click “Edit Page”. Find the video you wish to update, hover over it and you should see a pencil icon appear. Click the pencil icon to bring up the video options. From there you’ll have the ability to change you video using a link, or a video that you already have present in your media gallery.
I hope this helps. Please let us know if there’s anything else we can answer for you.