The phrase "first sketches" refers to the initial drawings or plans that are made when creating something new. It represents the first rough ideas or designs before any detailed work is done. Full definition
Maybe you'll get the very first sketch of an enemy that's in the final game! (kickstarter.com)
The idea of light and simple floors where could be possible even easily jump from one to another was always in mind from the very first sketches. (treehugger.com)
Each piece created and produced in - house allows for hands - on care from first sketch to last stitch. (threedots.com)