Trouble with Velux Header Video

Hi Everyone and thank you in advance for any help! I am building a website for a small practice and would like to figure out how to add a header video (only 10 seconds long – it’s a video intro) that plays on the opening screen when the site is first visited and after the video, I’d like it to go back to the background picture already in place. However, the page builder does not give the option to only play the video once (it plays over and over). Also, the theme recommends having the video be 2400×1300 pixels, but the video I have is 1920×1080 pixels (MP4) and does not play correctly (it is too low on the screen to read). I have disabled the video for now because it does not look right, but if it would help for me to activate it again, please let me know. So basically, I need help figuring out how to play a 10 second video one time when the website is visited and then return to the background image. And also, how to make it fit in the window.

Thanks for the help!

The page I need help with: [log in to see the link]