The holes have been poked (stabbed) into the leather, the ones to the left side placed at the correct angle and the ones to the right, have been either stabbed at an incorrect angle or in a careless manner. (The incorrect holes are for demonstration purposes only).

Here I am actually performing the hand stitching. Please note the position of my hands. I start stitching by running the lefthand needle thru from the back side of the leather and then pull it through with my left hand, raising it above the leather. Then, I poke the right hand needle through the hole with that thread going through the bottom of the hole. I then take the needles and thread into my hands and tighten the stitch, and then continue by repeating the process until I am at the end of the area being stitched.

Here is the finished stitching.

The sample stitch with comments

Here is the finished stitching.