I'm normally a programmer in unity so i know very little about modeling and all that stuff so sorry if this is a stupid question :) What i'm trying to do is make a background video for the main menu.
Never check the V.S.E. (the black screen you're seeing) for your rendered animation.
To see the outputed footage go to your file explorer and type in C:\tmp at the top (if you are on Windows). There you should see a string of image files for your movie. You can change the output file format and where it outputs to before rendering it. To see the rendered animation from within Blender, hit CTRL+F11.
It looks like you have not imported the rendered video into the VSE. Look at where your temp folder is and see if the file(s) are all in there. Then import the video or image sequence into the VSE.
Check the "outlier" panel (top right by default) and make sure you didn't accidentally click on and thereby turn off (disable) object in render.