You need to read a little bit more, before you can install a new ROM or flash anything you need a custom recovery like CWM or TWRP -- Now to make you aware if you do this you will trigger your KNOX warranty and void it.. so think very carefully before deciding. - make sure you read as much as possible and that you have the right tools, ROM etc to hand. Or you could find yourself in deep trouble.
Sent from my SM-N9005 using XDA Premium 4 mobile app
// Nexus 5 (D821) // Paranoid // UBER //