Federal Rule of Civil Procedure 38
Rule 38. Right to a Jury Trial; Demand
(b) Demand. On any issue triable of right by a jury, a party may demand a jury trial by:
(1) serving the other parties with a written demand—which may be included in a pleading—no later than 14 days after the last pleading directed to the issue is served; and
(2) filing the demand in accordance with Rule 5(d).