Here’s a quick how-to video of the Back Stitch, a common outlining stitch, which I have lovingly shortened to BS. Come up from the back and pull thread gently taut and then go down on the outline line, then come up from the back approx 1/cm further on the outline. then back through the previous stitch hole… easier to watch than for me to explain, I think! Lengths of stitches are of course up to you, but look good as long as they are consistent and uniform in length.
This video has no sound to distract you from learning the stitch.