Hi!
Does the external DVD drive work on another device? Test it on another computer to rule out a hardware problem.
When connecting the external DVD drive, press Windows + X > Disk Management > See if any device named CD or DVD appears with a blue or black bar. Sometimes it may be recognized, but Windows hasn't assigned a drive letter to it.
If nothing appears, press Windows + X > Device Manager > See if any drive appears with an exclamation mark icon ⚠️.