- copy_pop 45
The above command will copy the population with ID of 45 to the planet that is currently selected in your game.
- copy_pop 463
After selecting the planet you wish to copy the population to, running this command would apply the population of the planet with ID 463 to it.
Adjust the settings below to automatically generate a command. Once you've got everything right, hit the Copy button and paste it into the console in Stellaris.