"1" is where your needle comes up through the fabric
"2" is where it goes down again
You can do it. Work this almost like a split stitch. The difference? Instead of splitting the previous stitch, come up beside it. Repeat with your following stitches, working at a slight diagonal across your line, and keeping to the same side of your stitches (you can choose which side that will be). This stitch is great for curvy lines like vines and plant stems. (Maybe that’s why it’s called a stem stitch? Ya think?) This is also the most traditionally used stitch you see on vintage linens for outlines. Usually, those are stitched with just verrry few strands. I like to use all of 'em! Wanna see what it looks like?
The leaves and flower stem are all worked in a stem stitch. You don't have to learn any more stitches beyond this one if you don't want to. You could embroider for the rest of your life using only this one sweet stitch. Want to learn more?