Now you can begin stitch. You're going to create long stitches all the way across your hoop. Start in one direction (I chose top to bottom) and make all of those stitches first.
In the first picture, you can see how I used the ruler to guide my stitches and kept them aligned with the hash marks and nice and straight. This isn't necessary, but it really helped. Once you have all your stitches from top to bottom, do the same thing from side to side on top. (This is where a water soluble pen and a super tight hoop come in handy! You can see a few pencil marks because my fabric came a little loose while I was stitching.)
Unlike some other couching stitches where you have to weave your foundation stitches together, this one doesn't need that. It's going to look loose and messy at this point, but once we add our final step it will all fall into place.
Now that our whole area is covered in this grid, we're going to add individual cross stitches at every intersection to anchor the threads. You can begin anywhere in the area that you like. Simply choose an intersection and come up with your needle in the bottom left corner and go back through your fabric in the top right corner. Come up again in the top left, finishing in the bottom right.