Consider for a moment computer programming. The program is just made up. There is a sense in which it's not 'real'. You could call it a kind of 'abstract engineering'.
Put it like this: When one engineers a physical machine, they're limited by what is possible given the resources. A software engineer is only really limited by human imagination.
But this difference between what one can create with physical resources and what one can create with imagination isn't as fundamental as it might at first appear.
Consider yourself looking up at the night sky and viewing a star. The physical constraint on your resources, as a biological being, mean that what you see is a small, slightly sparkly dot just above you. But you know that really it's not small, not sparkly, and not particular in 'your' sky. Instead it's a gigantic sphere of plasma held together by gravity at an immense distance from you. Just like the computer program, we are having to image that this is what the star is, because we don't see it that way.
Now, you could at this point try to draw a distinction between imagining what stars are into existence and imagining a software program into existence. You could say that the star is *really there*, and it's only a limitation of our human situation that we see it as a small dot in the sky. But the computer software is really there, too. If one programs it, it will 'be'. It might not 'be' at the moment, but actually neither is the star. The star used to exist, but doesn't any more.
'Being' at a particular moment is not a necessary quality of something being true. The difference between the star that was and the program that will be is trivial, they are both really there, albeit at different points in time, and we can know about both through explanatory theories of the world.
ONE CAN DISCOVER SOMETHING THAT ONE FIRST HAS TO CREATE.