How do you unlock the bootloader of the huawei y5ii because I would like to flash TWRP
It looks like you need an unlock code from Huawei from them here, then unlock the bootloader with the code they provide using the fastboot command
fastboot oem unlock XXXX, where XXXX is the code they provided.
Then using fastboot and the TWRP recovery for your device, flash it using:
fastboot flash recovery nameofTWRPfile.img
That is the basics taken from XDA here.