A square base is sometimes called a preliminary base. It looks like you are transforming your large square of origami paper into a layered square shape.

To make a square base:

1. Fold the paper in half diagonally so it forms a triangle. Unfold.
2. Flip the paper over. Fold in half horizontally. Unfold. Fold in half vertically. Unfold. Notice that the diagonal crease appears to rise up from the page, while the vertical and horizontal creases seems to sink backwards. The diagonal creases are mountain folds. The vertical and horizontal creases are valley folds.
3. Flip your paper over and turn it toward you in a diamond shape. Flatten the paper to complete your square base, using the creases made in the previous steps as a guide.
4. Your square base is now complete.

The origami lily is a good example of a project that uses the square base. This design can be tricky for beginners, so don't get discouraged if your first few flowers are less than perfect.

To make an origami lily:

1. Make a square base.
2. Fold the left side of your paper in so it meets the middle crease. Unfold. Fold the right side of the paper in so it meets the middle crease. Unfold. Flip the paper over. Repeat this process with the other two sides. Then, use these creases to squash fold the paper so you have a series of flaps.
3. On the sides of the paper that have both the colored and white parts showing, fold the left and right points in towards the middle. Unfold. Pull the horizontal edge of the paper up and flatten into a diamond shape, using the creases you just made as a guide. Repeat on the other three sides of the paper.
4. Rotate the model 180 degrees.Now, the open points are on the top. Fold the top triangle of your smaller diamond shape up before you fold the left and right corners in to touch the center crease. Repeat on the other three sides of the paper.
5. Shape your flower petals by carefully opening up the top flaps of your model and curling the paper with your finger or a pencil.
6. Display your flower as is or add it to an origami bouquet.