First Officer reported the gear horn activation along with a low altitude alert from ATC during final approach to XNA. Flight climbed and continued the approach.

Narrative

Inbound to XNA approach cleared us to descend to 4000; asked us to look for traffic; and how far out we would need to go for the visual approach. I then responded with 'looking' and we would need to go to jadir which was the FAF. The approach controller gave us 5 degrees right and down to 3000. Shortly after reaching 3000 the controller cleared us for the visual approach and told us to contact tower. At this point we were approximately on a 10 mile modified base on a 300 heading. The captain went ahead and set 2200 since and I assumed it was since we were possibly going to be just inside the FAF and he began slowing to our flaps speeds and calling for flaps. I mentioned we needed to be at least 3 mile final per our FOM and the captain acknowledged. I switched over to tower and did my cleared for the approach flows (dinging seat belt sign and arming the thrust reversers). I checked in with tower and they cleared us to land and just after responding I looked back at the PFD (Primary Flight Display) and saw we were descending and saw the radar altimeter tape approaching. I quickly informed the captain we were about to pass 1000 ft at flaps 20; gear up (2288msl). Simultaneously the gear horn started sounding and ATC queried saying low altitude alert. The captain promptly disconnected the Autopilot and climbed to 1500 agl or approximately 2700msl. As we were still about a 7 mile base into the airport we stabilized the airplane and then configured the airplane with ample time after climbing and resequencing. The rest of the approach happened without issue and we debriefed what occurred once reaching the gate. I asked him if he thought SEYOD was the FAF instead of JADIR and he said that was the case. I reiterated that's why I mentioned at least a 3 mile final was needed. This was a high workload situation for me as Pilot Monitoring and I did not realize that the captain started his decent from 3000 to 2200 until about 2350. In hindsight while I cannot watch everything the captain does while still doing my job I should have queried him more about the tight pattern and the altitude being selected to 2200 more. I will be including a stabilized altitude in my briefings moving forward. Since we dipped below 1000 feet and were not on proper glidepath at the time of the occurrence there was a high likelihood that we were over a designated densely populated area and wasn't sure if it would possibly be a violation even though we were on approach to land.