Animating to absolute position

I thought that what I’m trying to achieve is pretty trivial, but apparently it isn’t - I’m trying to have a CMS gallery of videos, where the videos expand to full screen using animation, similar to this gallery:
When we were kids (scroll down and click a video)

How can I animate the gallery item from its position to have an absolute position? Using the “move” animation won’t work here, and I have no clue how to tackle this.

Thank you