Here are a couple of problems I ran into and how I fixed them.
Could not mount /sdcard/
Could not find any files on /sdcard/
Fix:
I pushed to /sdcard/0/ instead of just /sdcard/
(adb push supersu.zip /sdcard/0/)
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When I tried to install the universal driver, the interface driver (the one that Android pushed to Windows Update) was already installed.
Fix:
Unplug Device, Uninstall Interface Driver, Plug In Device
When Windows Update is trying to install the driver, click the "Skip obtaining drivers from Windows Update"
Then you can follow the steps in the video.
EDIT:
Didn't make it clear what this post was for, thanks for the reply though @ragnarokx