As far as I know you can’t actually aim a panzer in a map but you can fake it fairly easily.
You can insert a static model of a panzerfaust in your model for the visual and then use a func_invisible_user that triggers a shooter_rocket entity.
The angle property of the shooter_rocket determines which way the shot will go and the angle property of the panzerfaust model to make things look correct.
You could probably target the shooter rocket with an info_null as well.
One thing that you cannot do is make the ejected shell of the shooter_rocket look correct - it will always be ejected at zero degrees - this is because there is no angle being passed to the ejected shell in code (the angle for a player-fired panzer is passed to the shell from the player entity itself)
I have done this in a few maps before and it’s fairly straightforward.
The MLB maps also use the shooter_rocket entities - if you noclip yourself into the secret control rooms you can fire them off.