Step 1: Step 1

Picture of Step 1
Hole punch your cardboard (on the left hand side)

Add Duct Tape strips, covering the holes.

Step 2: Step 2

Picture of Step 2
Turn the cardboard over, and duct tape that side. Don't cover the holes.

Using the previous holes as a guide, use the hole punch to cut through the duct tape.

You can now cover the holes, and do the same process with the other side to cut them.

Step 3: Step 3

Picture of Step 3
Now you have the basic divider.

If you want to add tabs:

Take a strip of duct tape and fold it halfway on itself.

Stick it to the back of your divider.

Step 4: Step 4

Picture of Step 4
I made another divider with black duct tape, and put the tab lower than the first divider, You can make as many as you need, I only needed two.
I need to do this :)