Between here and Zabaldika the camino splits, and each of those splits also split and sometimes rejoin.
From Irotz you have two choices:
1. The most obvious but least exciting option is a concrete river path leading to the area de descanco. From this rest area you have another choice: climb the hill towards Trinidad de Arre, or go left on the longer but flatter meandering river path to Huarte and from there to Pamplona.
2. A smaller path that is also marked with a camino signpost leading to Zabaldika. Poor Zabaldika is bisected by the N road though and once you get there you will have to make another choice:
2A. Go left to join option 1 near the area de descanso.
2B (the cultural route). Cross the N road and make the small climb to upper Zabaldika. Here you will find the 13th.C. church of St. Stephen, an albergue, and wonderful hospitality. From upper Zabaldika you can continue west towards Trinidad de Arre, and you will rejoin option 1 shortly after it leaves the area de descanso.
The area de descanso is a basic roadside rest stop, which is handy but not half as practical as visiting upper Zabaldika where you can also get a rest.