So here is what I did.
#1- Get a sleeper.
#2- Using scraps of fleece and iron on stabilizer, cut out 2 rectangles about 2" x 3" and 1 rectangle of the stabilizer. Round off the edges of one end of each rectangle.
#3- Iron on the stabilizer to one of the fleece pieces (iron to the wrong side). Sew the 2 fleece pieces together. *I* sewed 2 long edges and the curve, right sides together using 3/8" seam allowance, and then turned right side out and zig zagged the opened end.
*You could place wrong sides together and just zig zag or serge around all edges, depends on how you want it to look.
#4- place the tab on the sleeper at the top of the zipper and decide where it needs to be placed. preferably covering th top of the zipper, some of mine I placed a little low and the top of the zipper sometimes pokes up into my daughters chin. She doesn't really care, but you know... it's a mom thing :-)
Fold under the short straight end. Pin into place. Stitch down the edge of the folded side. I stitched 2 parallel vertical lines, at the left most edge, stitching thru all the folded fabric.
#5- After you have your tab sewed on, fold it down into place. Visualize where your snap should be placed (1/2-3/4" from the curved edge) push a pin through the tab and sleeper front. Using a marking pen or chalk, mark where the pin is going into the tab.
Then gently lift the tab a little so you can see there the pin is going into the sleeper front. Mark that spot with your pen.
Carefully unzip the sleeper, leaving the pin stuck through the fabric and mark where the pin is coming through on the back side of the sleeper front.
#6- Remove pin and unzip zipper. Iron on a 3" square piece of iron on stabilizer to the wrong side of the front of the sleeper where you have made your mark.
#7- I have a snap press and can use plastic snaps, if you don't have a press, you can get a snap setter and metal snaps fairly cheap at fabric/craft store and websites. Apply a stud (male) snap to the sleeper front. Apply a socket (female) snap to the tab.