When you drag your Letterpress Box Stack out, you will see the above stack appear on your page.
Drop the stack you want to be effected by the Letterpress into the dropzone (please note, we can not guarentee the styles from Letterpress will override the the styles contained in the stack).
Choose your style, weight, lines and alignment of the text.
Now preview and enjoy! For an summary of the remaining settings please refer to the Letterpress Box Settings section.