Can't upload video clips in media manager pool

I have been trying to upload short video clips to the media pool but that has not been working. I've tried looking for the clip in the file explorer but it only shows images and when i tried dragging it to the pool it also didn't show up.

Are there specific video formats supported or have i been doing it wrong ? I've been trying to use a .MP4 clip and I'be read in the manual that i can use up to 2 clips

I'm using a Blackmagic Design ATEM 1 M/E Production Studio 4K

You can't upload video files. Only a collection of stills. You would normally export your video as a TGA sequence of still images. (only a limited number of frames depending on your switcher model and how you allocate the total number of frames between the media players).
This feature is not intended for normal vide clip playout, just for stinger type graphics.