This is a guide on how to stack furniture.
What you do is open up Restaurant City in the browser of your choice.
Go to decoration mode.
Follow the pictures below:
1) Cover the furniture you want to stack with the check mark
2) Move the furniture you want to stack onto the the thing you want to stack on (under the check-mark)
3) Click the check mark and let it save.
4) After you save you will notice the furniture you used to stack is gone.
5) Go into clothing shop and click the check mark (this saves thegame)
6) Save the game by clicking the top left save button (under the quality toggle)
7) Refresh the page and it will be stacked!