German Short Rows work by pulling the stitch from the row below up so that you remove the gap between the row heights.
Work to turning point, turn work. Slip 1 stitch pwise from left to right needle with yarn in front. Pull yarn over needle to back of work, creating a ‘double stitch’ on the right needle. Bring yarn to correct side of work for knit/purl, ensuring the double-stitch stays in place.
When you encounter this ‘double stitch’ on a following row, knit (or purl) it as a single stitch.