She goes so fast in that video!
I don't have a Storage app either. I don't know what version of the operating system that was in the video, but it isn't current. The Storage app seems to have been a shortcut to the Storage that is on the pulldown menu in the Library. You can access the same files and folders through ES File Explorer.
Once you find the Storage the video talks about, the rest of what she says seems right, though I would have to stop it a few times to really get what she's saying!
Edit: ptsenter! Your answer beat mine and you are so right!

It
is now called Device Storage and works exactly as advertised, at least on my PE.