First, you will need some supplies:
two coordinating fabrics (about 1/4 of a yard of each is plenty)
something absorbent for the inner layer (I used natural cotton batting)
snaps or velcro for closure
First step, cut the rectangles out of your fabrics. For my kinderpack, I used a size of 7" x 11". For another type of carrier like Ergo or Tula, you can cut them a little shorter on the width as the straps are not as wide. Cut two of each of your fabrics and also cut two of your inner layer.
If you are planning to add ribbons or other embellishments, pin them onto one of your pieces now. I chose to use three ribbons, one yellow grosgrain, one small white satin and one medium red grosgrain. I like to use a variety of textures and widths so they're fun for little fingers. You can attach these to the top of bottom of the drool pads depending on your preference. If your little one rides arms out, some like the loops on the top so they are at their arm height. If your kiddo rides arms in, loops on the bottom may be more practical as the dangling toys would be easier for them to access.
Whatever your preference, loop the ribbons and pin in place to the RIGHT side of one of your fabrics. The raw edges of the ribbon will align with the raw edge of the fabric. This will enclose them completely inside your front and back pieces when sewn together. (Don't worry - they will get turned out just like your fabric!)
Now place the other fabric on top of the first (with the ribbons if you added them) with right sides together. Finally, add the middle layer to the stack and pin all three layers together.
Sew all the way around the outside with a 1/4" seam allowance. I backstitch over the ribbons a few times to make sure that they won't come loose with toys being pulled on. Make sure to leave an opening on one of the edges of about 2-3 inches so that you can turn right sides out.
Once you're done sewing, clip the corners of your work so that you can create better points in the corners when it's turned inside out. Now turn your work. You will want to press with a hot iron to make sure that you have everything nice and flat for topstitching. Press under the gap from turning as well.
Now stitch all around the outer edge of the drool pad. I use a scant 1/8" seam allowance because I like the look of a close stitch, but you can use as wide a stitch as you like as long as you catch the edges of your hole to sew it closed.If your machine has decorative stitches, that can give them a fun look as well.
Now attach your velcro or snaps in whatever fashion your choose and you are all set!