Creating environment by coding

Hello everybody,
I am sorry if this topic might seem a bit “noobish” but this is the first time I put my hands on Unreal. What I am trying to do is developing an environment for my game by coding. I have to read a .txt file (or similar) which is easy to do in c++. According to that file, I have to build a simple environment (walls, floor, lights etc.). Unfortunately I didn’t get yet if this is doable by coding. I am trying to follow several tutorials, one of those is the following one:

But what I am trying to do is a bit different. Let’s get a bit deeper and take an example in such a way that I can understand better: what I have to do to create a simple box with a mesh and texture by coding? Can you kindly refer me to some tutorial or guide? Thanks in advance for your attention and patience.