There are multiple variants of this device. Make sure you’re viewing the right one.
Special boot modes
Recovery: The bootloader does not allow using hardware buttons to boot to recovery. After apx flash, the device will boot directly to recovery. After installing Lineage, normal methods can be used to reboot to recovery.
Bootloader/Fastboot/Download: With the device unplugged, jump the FRC REC pin, then plug in. Remove the jumper once apx enumerates.