Hello, I want to create a small program for 3D modeling, although technically it is not one, according to the idea it should be a hangar, and in it I should create rockets and other spaceships from already prepared models of engines and other parts, but also with the ability editing the body using the creation of 3D models, well, it’s logical to save it on some flash drives in the game, which the player will have in his inventory. I’m new to game development and programming, but at least I know the basics. I want to make an editor similar to the one in Kerbal Space Program Scrap Mechanic, or better yet, like in the game Shtormworks, that is, connecting each element to power, a button for example, and another element and creating logical elements. I didn’t find anything like this on YouTube or other sites on the Internet so I decided to ask this question here, maybe someone can help, please 
Hey there @TNTCARDBOARD! Welcome to the community! Speaking from a high level, a vehicle construction system and a building system are actually basically the same thing, so many tutorials for a building system can teach you most of what you’d need for a modular vehicle system barring a couple of (admittedly complex) problems.
One big thing a building system won’t account for:
Physics. If you were going for something like kerbal where your pieces can snap off/change based on physical positioning, this won’t be covered by statically attaching pieces. You’d probably look into physics constraints for those, but be careful, Kerbal was built for handling physics and it still can get out of hand very easily.
I seem to have found how to do this, and how to create physics, but I don’t understand how to do something like electrics like in the same games Scrap Mechanic or Shtormworks, and how to make such saves in the form of the same flash drives in the player’s inventory 