From the US Copyright Office, the steps on Copyrighting Literary Works:
"Follow these steps to register your book, manuscript, online work, poetry, or other text:
Make sure your work is a literary work. Literary works may be published or unpublished and include nondramatic textual works with or without illustrations. Computer programs and databases also are considered literary works. Here are more examples and specific information.
To register serials and periodicals, see the Serial Works instructions.
Put into one envelope or package:
a completed application Form TX or Short Form TX and Form CON if needed (choose which form to use) (go to the site for downloading these forms as PDF documents)
a $45 payment to "Register of Copyrights."
nonreturnable copy(ies) of the material to be registered. Read details on deposit requirements. Please read this important notice about mail delivery disruption.
Send the package to:
Library of Congress
101 Independence Avenue, S.E.
Washington, D.C. 20559-6000
Your registration becomes effective on the day that the Copyright Office receives your application, payment, and copy(ies) in acceptable form. If your submission is in order, you will receive a certificate of registration in approximately 4 months.
For more details about copyright, please see our information circulars."
About the Copyright notice, that c within a circle, the site explains:
"The use of a copyright notice is no longer required under U.S. law, although it is often beneficial. Because prior law did contain such a requirement, however, the use of notice is still relevant to the copyright status of older works.
This circular discusses both the copyright notice provisions as originally enacted in the 1976 copyright act (title 17, U.S. Code), which took effect January 1, 1978, and the effect of the 1988 Berne Convention Implementation Act, which amended the copyright law to make the use of a copyright notice optional on copies of works published on and after March 1, 1989. Specifications for the proper form and placement of the notice are described in this circular.
Works published before January 1, 1978, are governed by the previous copyright law. Under that law, if a work was published under the copyright owner’s authority without a proper notice of copyright, all copyright protection for that work was permanently lost in the United States."