Surfaces pick one, then paint on the plan
Your yard starts as a plain 1 ft grid with nothing painted; the eraser clears a square back to the grid. While a deck is placed, painting goes around it (the deck covers that ground). There is no deck until you add one with "Custom deck"; "No deck" takes it away again. Drag on the plan to paint 1 ft squares, or pick Rectangle and drag a box. Tap "Done painting" to move products and look around again.
Deck position in the yard