Hi @digifessor,

You can use the wpForo "Admin note" feature.

<video width="320" height="240" controls>
     <source src="SampleVideo.mp4" type="video/mp4">
</video>

For example if you want to insert the video below, follow the steps below: 

1. Navigate to Dashboard > Forums > Tools > Antispam tab, add <source> tag with its attributes in "Allow extra HTML tags" section.

source(src type),

2. Switch to "Text mode" in Admin Note editor and try to add the HTML code with marquee tag, save it and check on the frontend.

The following support topic may also be helpful for you:

https://wpforo.com/community/how-to-and-troubleshooting-2/html-content-on-admin-message-on-forum-front-page/#post-20205