First, go to your userpage. Then go to the section "More badges you can earn". Then go to the bottom of that section and it says "customize badges" if I remember correctly. Then when in the badge customizer, look on the right of your screen and go down to the section about creating a new track. there should be a section where you type in the category that you want to make a badge track for. Then once you do that, you can rename the badges and add images. If you need any other help, just ask me.