yeah but i want to understand the meaning of word " configuration".This is why context is important - it is still a design layout which is being discussed, but in this case the design layout which is used in the initial configuration. I imagine that this is about a piece of software, and chapter 4 discusses how the default layout (the one in the initial configuration, without adjusting or personalising the software) can be developed (meaning changed).
Sorry for replying late,it is "Aircraft design by Raymer"In general terms the word configuration means the arrangement or organisation of items within a whole. But what it means precisely in your context is impossible to say without a better understanding of the subject of the text. What is the source of these quotes?