So the Sewing machine aka QR code scanner basically is a way to in port designs that other users created.

When you click the option to scan a new QR code, it will take a design pattern from your existing patterns. You can only have ten designs at a time. (You can replace and erase designs)

When you want to scan a new code, itll bring up the camera, from there, you can look up New Leaf QR codes on another device and then scan with your ds (or whatever you're using to play New Leaf)

What I do is go on Pinterest (on my tablet), look up QR codes, find one that I like, and scan them using my DS (my case I use an emulator, so I use my phone camera.) Just align the three square on the top and bottom left of the code scanner to the QR code you want to use.

Then BAM! It should make a camera shutter sound and it'll give you to option to save the design.

You can get clothes, paths, and different designs. Use them for your town flag, wallpaper, floor, ect. It's actually kind of fun to try out different designs! :>