After selecting an object from the carousel, that object appears along with your cursor until you place it into your design.
Initial Placement
Placing in the Floorplan View
Post-selection, the object appears along with your cursor until you place it into your design. As you move the mouse near one of the walls, the object snaps itself to that wall or to the corner formed by that wall. Wherever you are satisfied with the position of the object, click once on that very point to place the object.
Placement and Auto-rotation in the 3D View
Post-selection, the object appears along with your cursor until you place it into your design. As you move the mouse near one of the floors or walls, the object snaps itself to that floor, wall or to the corner formed by that wall. Moreover, depending on the wall you draw your mouse near, the object will automatically rotate itself to align with that very wall in the correct direction. Wherever you are satisfied with the position of the object, click once on that very point to place the object.
Note: Auto-rotation works only in the 3D view