When looking to create a new solution starting from premade pieces you need to have a precise and exhaustive inventory of all the pieces and how they can connect with each other.
Design is about finding new and useful connections. New, compared to the solutions found until now, otherwise you would have already solved the problem. Useful because they are satisfying the needs, wants and desires of the final users.
It’s not wise to try to arrange the pieces without having a clear and shared understanding of their functions and their potential for connection, it could be inefficient or, worst, harmful.