Instructions
Go to your Penguin̵7;s igloo. Click the ̶0;Edit Igloo̶1; icon -- the measuring tape image -- and then click the ̶0;Buy Items̶1; icon -- the "Better Igloos" image.
Check every page of the catalog for Secrets items, including the magic Portal Box. Roll your cursor around on each page until it turns into a hand that indicates a hidden item and then click to see the item. In the Better Igloos Mar-Apr catalog, the box appeared if you clicked the Wishing Well. If you don̵7;t find the box in the current ̶0;Better Igloos,̶1; wait until the next edition and continue to check until you find it.
Buy the Portal Box once you reveal it. Click the ̶0;Buy̶1; button and confirm the purchase to add it to your Penguin̵7;s items inventory.