At around 11 min Eber shows the stand offs and talks about the installation into the case. They have to be installed in the correct place depending on the motherboard. You can check that by looking at the holes in the motherboard that the screws will go through to connect to the stand offs. Some cases come with the stand offs pre-installed for ATX form factor motherboards, some just have them in a bag so you can install them yourself. Sometimes you'll have to remove some or move them to make it work right for your particular motherboard.
Hope that helps.