Pieces you need:

 2 large rectangles

 2 arches

2 triangles 

2 arm-rests

2 semi-circles

1 play mat

Steps:

✔️ Step 1: Place the playmat on the ground standing in an L formation.

✔️ Step 2: Place the large rectangle down on its long thin side parallel to the L and touching to create a rectangular U shape. Place a semi-circle on top of the rectangle to create a window.

✔️ Step 3: Place the other large rectangle on top of the U to make a roof. You can add a semi-circle on top of the roof for decoration.

✔️ Step 4: Place the arm-rest rectangles or triangles on the floor standing tall in front of the U to extend the length of the fort.

✔️ Step 5: Place the remaining two small rectangles or triangles on the ground. One will be touching the previous placed piece and the other side will have about a foot of space between them.

✔️ Step 6:  Place the arch on top of the previously placed pieces to create one arched doorway at the front of the fort. Use the remaining semi-circle as a second doorway on the side of the fort. 

Check out past build of the months here.