u/IRideTheDruggyBuggy

I will be creating a strap for a sling bag and found a cool mosaic pattern on ravelry however I am having trouble deciphering what is meant in the included picture. I feel like it says to work the area with two exes by double crocheting into a stitch of the row right under it but it says crochet into the double stitch? The diagram shows a single stitch right under unless it means work into the stitch right under and to the left of the stitch. Not sure if that makes sense. Can someone clarify please?