First thing to do: unlock your bootloader.
It is mandatory to customize your phone. You want to do it as soon as you get it because it needs wiping your internal memory and you don't want to start over once you'll get your phone fully seT.
There are many guides, don't use toolkits but adb and fastboot commands
Sent from my Oneplus One
- Recovery: TWRP recovery 184.108.40.206
- Rom: Stock CM 11s
- Kernel: Stock
- Bootloader: Unlocked
Past Devices: Nokia N95 8 gb - iPhone 4 - Galaxy Nexus - Galaxy S4