The following line appears in Pope's poem "The Rape of the Lock" in Canto One, line 37. Explanation of the line needs to be completed within the context of Canto One as a whole.
In Canto One, Pope introduces the Beautiful Belinda. The Sun (a muse in the poem) has been evoked so as to provide the beginning of the day (which the sun historically symbolizes). The people of the household, therefore, are described as going about their typical morning routine.
Readers learn of Belinda and her relationship with the Sylphs- they are her protectors- through a description of her dreams. Her main protector, Ariel, tells her in her dream that the day will bring about "some dread Event". After awaking from her dream, and the warning, Belinda proceeds to ready herself for the day.
Here Files of Pins extend their shining Rows,
Puffs, Powders, Patches, Bibles, Billet-doux.
Now awful Beauty puts on all its Arms;
The Fair each moment rises in her Charms,
Repairs her Smiles, awakens ev'ry Grace,
And calls forth all the Wonders of her Face;
The lines shown above tell of Belinda readying herself for the day. The "files of pins" are hair pins placed into her hair in rows. The following lines depict the things Belinda needs to get ready so that all can look upon "the Wonders of her Face".
The line is simply referring to Belinda having her hair done.