A CRJ900 First Officer reported failure of the landing gear to extend during approach; resulting in a go around. Emergency procedures are complied with. They were initially unsuccessful; but manual extension was successful. Nose wheel steering was inoperative and a tow to the gate was required.

Narrative

On approach; approximately two miles prior to the FAF; as the Pilot Flying (PF); I asked for 'gear down'. The Captain; Pilot Not Flying (PNF); selected the gear handle down; but nothing happened. A few seconds later we received a triple chime warning message followed by a 'gear disagree' aural tone. I initiated a go-around as the PF announced the go-around to ATC and advised them that we had an unsafe gear indication and to 'standby'. ATC vectored us to the right and out towards a wide downwind at 4;000MSL. After the airplane was cleaned up I called for the checklist and informed the Captain that I would fly and handle radio calls. The emergency procedure in the book called for the 3B and 2A hydraulic pumps to be selected on; followed by cycling of the landing gear. When the gear did not drop following this procedure; we attempted it again but with no success. The procedure then had us pull the manual release lever; to which the main gear dropped and locked in place within a few seconds; and the nose gear was locked into place in about twenty seconds. The Captain informed the Flight Attendants of the situation and made an announcement to the passengers via the PA. He also informed Dispatch of the situation and told them we would be making a precautionary landing. We also informed ATC that we were receiving a 'down and locked' indication; however were unsure of the nose wheel steering upon touchdown and requested the assistance of emergency vehicles. It was at that time we declared the emergency. We set up for the visual; backed up by the ILS. On touchdown we received 'nose wheel steering inop' caution message; but used differential braking to decelerate the aircraft and take the high-speed runway exit. We advised ATC and ARFF that no more assistance was needed from them; but we would need a tug to pull us to the gate. We waited for approximately 30 minutes for the tug but were pulled to the gate without further incident.