Hold up the side with a rubber band...With your fingers, press down the tabs to the bottom of the chipboard.

After the tabs are glued down, you can start decorating, stamping, etc...the inside.

Cut a square this is 3" less 1/8" to fit inside. Glue into place.

Re-punch your holes and put in your eyelets.

Here you have it...Repeat the process for all the other parts, stack up and voila..

On my finished tree, I added a piece of chipboard under for a snug fit.