Hello, i have recently bought this amazing game and have managed to complete the main story.
i have the 3rd building but i know you can get add ons to the building can you still get them after the main story and if so, how does one unlock them?
just keep on playing, train your worker research everything you can get into you fingers and eventually the additional buildings will come. or read on the Game Dev Tycoon Wiki there you will find a lot good things to know.
Ah thank you!
I did search on the wiki and I couldn’t seem to find anything 
Anyway, thank you for the help ^^
oh i just remember! you need to train the Design and Technology Spezialist!