Hi first off, if u want to flash custom rom or kernel, u have to unlock your bootloader.
After that you can install custom recovery and flash the rom/kernel of your choice.
Or u could go the fastest way by
-Unlock your bootloader
-downloading the rom (pac) and the kernel (e.g. meow kernel) to your SD card
-Via pc in cmd command fastboot flash boot boot.I'm
-Boot in recovery when led is on(volume up)
-Flash pac rom and gapps if u need them, if u want custom kernel, flash meow after that.
Hit thanks if I helped ya
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