This is the biggest hurdle. In mid-2018, Huawei shut down its bootloader unlock code service. If your Y6 Prime was purchased after this date, you might be stuck.
This will wipe your data. You are responsible for your own device. huawei y6 prime custom rom
If you manage to unlock the bootloader, here is what you will find: This is the biggest hurdle
In TWRP, perform an Advanced Wipe of Dalvik, System, Data, and Cache. perform an Advanced Wipe of Dalvik