This pattern drafting tutorial for dressmaking teaches the pivot method of dart manipulation. The other dart manipulation technique is the Slash and Spread Method available at this link: https://youtu.be/ul4Qe7BspI4
Technical Drawings, also called technical flats, explain the design details in an outfit. Without a technical drawing, you will be unable to create the pattern. This video gives an overview of why you need technical drawing in dressmaking.