You need to unlock your bootloader, install custom recovery (TWRP) and then install a custom ROM (I use LineageOS). It's optional to install Google into AOSP-ba

You need to unlock your bootloader, install custom recovery (TWRP) and then install a custom ROM (I use LineageOS). It's optional to install Google into AOSP-based ROMs. You need to find instructions based on your specific device. Each one is different.