Detailed instructions for working a group puzzle of type 'Demonstrably'

This is a signature puzzle named 'Demonstrably'

The 12 elements in each group of this type of puzzle are: D, E, M, O, N, S, T, R, A, B, L, and Y.

Every group in the puzzle must contain exactly this set of elements.

Each row is a group numbered as shown in this Demonstrably figure.

In a Demonstrably puzzle, each row is a group numbered as shown in the figure above.

Each column is a group numbered as shown in this Demonstrably figure.

In a Demonstrably puzzle, each column is a group numbered as shown in the figure above.

Each 4x3 rectangle is a group numbered as shown in this Demonstrably figure.

In a Demonstrably puzzle, each 4x3 rectangle is a group numbered as shown in the figure above.

Each eye is a group numbered as shown in this Demonstrably figure.

In a Demonstrably puzzle, each eye is a group numbered as shown in the figure above.

The elements that make up the smile are a group and are marked with '1st' in this Demonstrably figure.

In a Demonstrably puzzle, the elements that make up the smile are a group and are marked with '1st' in the figure above.