Begin your citation with the Bluebook abbreviation for Federal Rules of Civil Procedure. This should appear as follows:
Fed. R. Civ. P.
List the rule number you are citing. If you are citing a section or subsection or the rule, include these letters or numbers. Sections and subsection should appear in parentheses. For example:
Fed. R. Civ. P. 4(c)(3).
Position your citation after the sentence in which you quote the Federal Rules of Civil Procedure. Your citation should appear after the period. For example:
A marshal or deputy marshal may serve the court "at the plaintiff’s request." Fed. R. Civ. P. 4(c)(3).