I think we can use ISS as an example.
"When ISS is completed it will cover an area as big as a football pitch and weigh 455 tonnes. It would have been impossible to build ISS on the ground and then launch it into space in one go; there is no rocket big enough or powerful enough. To get round this problem the Space Station is taken into space piece-by-piece and gradually built in orbit, approximately 400 km above the Earth’s surface. "
So you would design the entire ship in your tech editor and then you would start sending its components, parts and materials into orbit, where they would be put together automatically. So basically you design it, make a piece, send it into orbit, make a piece, send it into orbit, rinse and repeat.
As for the landing, these giant things would be in no way able to land anywhere. For that, you would have to design another ship - a much smaller one.
Also, I imagine that once you make something yourself, it becomes available as a “part”. Have you ever made a cannon? Then you can just slap that bad boy onto your ship, you deserve it (the resources would still cost the same, to make the player want to be efficient with their designs). What this means is that once you design a ship you just can give an order to make 10 of them, 100 of them, whatever you want. Also, I imagine, once you make something, you can always open the editor and edit that thing. Because technological progress. So even technology would have “generations of evolution”, (more like marks), just like cells or.