A cover letter normally lists everything that is included in the package. G-1145 is not necessary, but if you send it with your package it should be the first page on it. If USCIS receives it with your package, it will let you know by email that your package was received and accepted.
[This answer is for general purposes only; it does not constitute advice and does not establish an attorney-client relationship.]
there are two ways to proceed: 1. read the instructions on all forms and underlying law. 2. hire an immigration attorney. This forum is not among those options.
NYC EXPERIENCED IMMIGRATION ATTORNEYS www.myattorneyusa.com; email: firstname.lastname@example.org; Phone: (866) 456-8654; Fax: 212-964-0440; Cell: 212-202-0325. The information contained in this answer is provided for informational purposes only, and should not be construed as legal advice on any subject matter.