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

This is a signature puzzle named 'Preston'

The 7 elements in each group of this type of puzzle are: P, R, E, S, T, O, and N.

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

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

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

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

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

Each septomino is a group numbered as shown in this Preston figure.

In a Preston puzzle, each septomino is a group numbered as shown in the figure above.