actually I found the solution now.
So if anyone else is struggling, here you go:

If you go to the ghost building mode on one of the planets where you are currently not at, you can build the ghost turret with the desired ammo.

happy building

Hi everybody! Space Age is keeping me very busy :) Great expansion!!! I saw Nilaus making a ghost turrent with ammo in one of his videos. But I fail to do it :( Can someone help me and please explain what key I need to press? How can I open the "set ghost cursor menu" ? And how do you load...