I did it!
With the help of tutorials, I finally had the courage to add a binding to a baby quilt. I usually do a pillowcase turn or bring the backing to the front. But on this one after I did the diagonal stitching through the blocks, I found out my backing wasn't as big as I thought it was so it was time to try a separate binding. I am pleased with the mitered corners. I need a little more practice with sewing close to the stitch line from the back as I missed the binding in a few places on the back. Overall, I am pleased with it. The top was given to me so I just needed to sandwich and finish it.