A320 pilot reported landing gear failed to extend during approach. Flight crew performed manual gear extension and landed safely.

Narrative

While approaching ZZZ on the ILS to XXL; we received a ; HYD G RSVR LOW LVL message ; when moving the flap lever to flaps two. Upon receiving this message; we were on final and continuing the approach. Any immediate threat was not obvious so we continued while following the ecam actions. After lowering the gear handle it was obvious the gear did not come down both audibly and by the position indicator. We performed a go-around and advised ATC of our situation and [requested priority handling]. We were given vectors as we ran through the QRH for the above message. When this was complete; we briefed the Flight attendants; set up for the approach and ran all appropriate checklist. We put the gear down using the manual gear extension per QRH. We then commenced the approach; landed and taxied to the gate without further incident. Upon arriving at the gate; we were met by maintenance where we filled out the appropriate write up in the logbook. Assessing the situation after; I feel that the [request of priority handling] was the proper course of action as we did not know what the outcome of a manual gear extension would be at the time. I do feel; however; that I allowed our situation to be rushed and wish I would've taken a few more moments to brief the flight attendants more thoroughly about what exactly to expect on landing and what was happening. Before commencing approach; we neglected to arm the approach mode; which caused us a bit more work as I disconnected the auto pilot and auto thrust upon noticing this for landing. We wanted to get the gear down as soon as practical; as we have never done a manual gear extension live; and wanted to know early as possible that we would have a good down and locked indication. Trying to limit the amount of flying time with the gear down; as well as the loud noise we were dealing with; played a major factor in feeling pressure to expedite this second approach.