I think I've figured out how to hem now
OK so basically for both non stretchy and stretchy fabrics, you use the same technique but with different stitches
Like for sturdier fabric you fold it and ensure the raw edge is inside BUT you use a straight stitch
And then for stretchy fabric, you do the same but use zizag
Dk why I was complicating the process but yup think I figured it out.. right?