“Found very hard to keep all the layers together and finish the seem neet”
yeah, that’s the crux of the project
I mark a line on one of the fabric pieces (the one that will eventually be inside the quilt) where the edge of the finished quilt will be, cut the two fabric pieces and insulation at least an inch larger
Then put a bunch of hand stitches all the way around, maybe 1/4 inch inside the marked line. Be very careful to align all the pieces. Start with hand stitches at the 4 corners, then do a bunch in between. A real sewer would probably use pins.
Then sew all the way around, about 1/4 inch inside the marked line. That will stabilize the insulation.
Then cut one piece of fabric (which should be the inside) and the insulation along the marked line. The outer piece of fabric should be at least 1 inch wider.
Then fold over the outer piece of fabric to cover the raw edge of the inner fabric and insulation, and hide the raw edge of the outer piece of fabric, and sew it. You should be sewing through inner fabric, insulation, the outer fabric, and the outer fabric again folded over.
I haven’t done that with quilt, but did it with a vest. There’s an article with pictures somewhere. This technique should work equally well with a quilt.