Instructions
Press "Start" to pause the game and open the menu.
Select the "Plans" menu and press "X."
Use the arrow buttons to select the "Shelter Plans" menu. Press "X."
Use the arrow buttons to select the house you want to build. Press "X."
Use the joysticks to place the hut where you want it. Press "X."
Press the "Triangle" button to exit each of the menus.
Walk up to the incomplete structure and press "X" when the "Build" option appears. Watch your Sim build the hut.