Default Rooting issues..?

So, I've been using this video to try and root my Nexus 7. This is my first Android device, and it's not going well.

I've been using the tutorial from ""

To attempt a root, and I don't have any problems, no errors or anything. Everything goes pretty smoothly, until the end. The first time, it installed and there was a notification about SU permissions being granted, but a root checker said it wasn't properly rooted. Tried to open SuperSU and it said "There is no SU binary..".

So I thought, alright, I'll go back into recovery mode and install the file again. Again, went smoothly but this time when my Nexus booted up, SuperSU was gone.

I could really use some help getting this going properly....