Are you using a pattern? Do you have an image? When I google, I just get old pattern images like the one attached. I haven’t come across these very often and never made one myself, so I don’t know if this is a typical construction. Looking at my image, it looks like the center front and shoulder are one piece. The side front is attached at the shoulder and, most likely, back piece. The side front and center front is stitched together to just below the bustline area and then the rest of the seam is just left open and hemmed. If you want to add a lining, I would construct the outer shell and lining separately and then place them together, wrong side to wrong side, basting around the neckline area. Then finish the neckline however you planned to do that, like with a collar or something. At the hemline areas, I would just hand tack the lining to the outer shell.