Hi Mathias,
First, look into how to create a modal or pop-up using interactions. You’ll find some great videos on Youtube, and probably quite a few cloneable in Made in Webflow. Once you have that, you just drop a video element inside, but here’s where things get a bit sticky-
First, you don’t want to use autoplay, because you want the video to start when the modal opens, not when the page loads. You’ll need custom code to do that, and how you write it depends on the player you’re using.
Webflow uses Embed.ly which appears to use Player.js pretty consistently, so you have have your button click open the model ( via the interaction ) and also start the video ( custom code → Player.js start ).
Similarly when the modal is closed, you need some custom code to pause the video as well. I usually use a MutationObserver when I’m building these on client sites, but there are other approaches.
Unfortunately I’ve not see any no-code solutions that can build the full experience you’re trying to recreate. Drop me a message if you need coding help.