What do I need to do to advance when it says decorate?

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I am stuck it says I have flowers in storage and I need to redecorate how..

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It means you need more Flowers added to your island to proceed. How many more you need is indicated on the main island screen, top right, next to the Flower icon. If you lack enough Flowers in storage items, you can acquire Flowers by buying decoration, renovating a landmark, upgrading a 3x3 building, or sending Jack's plane on a Flower delivery. If you buy decoration, the Flowers will not count until after construction is complete and the red ribbon is removed.