She leaves the papers in. Every hexagon in the flower keeps its paper template until the moment it is stitched down, and only the center one comes out early. Pull them all before you start and the flower turns flimsy in your hands, which she shows rather than says.
Sherri McConnell of A Quilting Life appliques a Grandmother's Flower Garden block onto a plain background, and the same technique does a Dresden and its center circle, or any shape with straight edges. No curves in the whole video. She says outright that this is the best way to learn hand applique, because nothing in it can go wrong the way a curve can.
The preparation is where the detail is. She cuts the background larger than the pattern calls for and trims it after, because the stitching draws it up a little. She folds it in half and in half again and finger presses, no iron, to get centering lines, then lines up the seams of two opposite petals with those folds. Then she checks it with a ruler rather than trusting her eye, finds 1 5/8 on one side and 1 6/8 on the other, and moves the flower. Short applique pins go in the center and in every other petal, and come out as soon as two sides of a hexagon are down.
The stitch itself is a hemming stitch, a quarter inch apart or slightly less, with the needle coming up as close to the folded edge as she can, so nothing shows on top. A stitch lands in every corner of every hexagon, and another at each inner point. She works without a thimble on purpose, so she can feel the needle arrive under her finger.
It went up in 2021 and has passed eighty thousand views, which for a twenty minute hand sewing tutorial is a lot.
Two things are worth the time even if you applique already. She threads three needles before she sits down. And she finishes by knotting on the back, then running the needle through the backing toward the center before cutting, so no tail shows through a light background.
If you would rather do this by machine, we wrote up the other half of it: blanket stitch applique, with the points, the curves and the inside corners.
Her channel is A Quilting Life, where the rest of the hexagon and Dresden series lives.