All you need is ¼" plywood and a bit of wood glue
I made this about a year ago for my mom to replace our old rusting tin divider. She showed me a picture of one she saw at Walmart and this was my first attempt... If I had tried again I would have made a few improvements, but she liked it so I didn't try again. As I said, I made this a while ago, so I don't have pictures of the process. But I've got the finished product, hopefully you can go of that.
What you will need
How to do this project
You can add or remove the extra dividers