After uploading your video, you'll be able to change any of its settings right there, on the same page.
Under VID SETTINGS (on the left side of your video), you'll find a section called 'Style'.
If you expand it, you'll be able to switch the foreground and background colors of your player by clicking on the colored boxes and selecting one, or typing in the hex color you want.
You'll also be able to show or hide any of the controls on your video: big play button, small play button, seeking bar, volume and fullscreen toggling.
Next, you'll be able to change a couple of play options: you can enable auto play and disable pausing on any of your videos.
Note: At the moment, disable pausing is tied to the auto play setting. Meaning that if you enable disable pausing, the auto play option will be enabled as well. However, you can enable auto play by itself :)
After making all the changes you want, refresh your browser to get a preview of them. Do this as many times as you want, until your video looks great. After getting your video to look the way you want to, click the Publish button at the top right of the video.
This button will push your changes live, so your audience can see them ;)
A note on Auto Play and Safari:
Disabling all the controls on your video does not play well with Safari 11+ for desktop when autoplay is disabled. Why? Well, since the UI is disabled and the video is not playing automatically and there are no buttons on the screen to hit play, there is no way to play the video.
This is an issue just with the newest Safari versions (11+). Older Safari versions and other browsers work perfectly with all the combinations of settings.