Okay, ladies, this is really simple! Just cutting, pinning, and straight-line sewing. There are probably *better* ways to sew up a hotpad, but this has got to be the easiest.
You're going to need your hotpad fabric and some batting, nothing fancy:
Now, cut out your fabric squares, about 10 inches square. Then cut out batting about 1 1/2 inchessmaller on each side (maybe 8 1/2" square) . I used two layers of batting and simply cut a rectangle and folded it over double.
Now press your fabric nicely (don't press the batting!), then take each square and press under a seam allowance. Some steam in your iron or a water spray bottle will help it press nicely and hold its shape:
Now just sandwich your layers together. You're hoping that your fabric edges come out just a smidgen farther than the batting. If the batting's sticking out, just poke it in--it doesn't matter if it bunches up a little bit. Pin everything together securely. Maybe your corners will match up better than mine! I always end up tweaking mine right as they are going under the needle. In sewing, whatever works is fine, and a hotpad is no place for perfectionism!
Stich all the way around the four sides, as close to the edge as possible without going off. Now get brave and zip the hotpad through again a few times in some random lines--maybe a smaller concentric square, or an X, or three diagonals. The only thing I would caution you about is making more than two lines meet at any given point--the batting gets too compressed to give you good protection from a hot pan. Feel free to work an asymmetrical pattern--that's part of the "homespun charm" you're going for.
You may find that the top layer wants to bunch up a tiny bit as you run the hotpad through, making a tiny "bump" or gather as you meet up with a stitching line. My attitude is, who cares? Because it's a really cute hotpad and it's going to get used and stained, and a little bump is no big deal!
Have fun!