Hey, so i’m totally new to sewing (garments at least), and am working on my first project, the Jakob men’s shirt. I’m having a bit of trouble grasping the sleeve seam concept here. Looking at other men’s shirts that i have lying around, i see that there is only one seam that encloses the sleeve, and it appears to be a flat-felled seam? (i’m using flannel shirts as reference as i’m working with flannel) I’ve seen tutorials on how to sew a flat felled seam, but they all use two separate pieces of fabric, whereas i need to use one, to make an enclosure. How to i sew up the sleeve without sewing one wall of it to the other?