i share technical info on my q-tech-info channel you can learn easy on my channel
commands
adb devices
adb reboot bootloader
fastboot devices
fastboot flash boot (boot file path)
fastboot --disable-verification --disable-verification flash vbmeta (vbmeta file path)
Roots files
http://fumacrom.com/18U2z
adb software
http://fumacrom.com/hGgD