Caldas de Rei is best known for its hot springs (caldas). They still exist, but the tradition of putting your feet into the fountain is discouraged for obvious hygienic reasons. All the same really, a hot soak after a hot day of walking isn’t the best of plans. To see the springs (and to follow the camino), turn left after crossing the first bridge in town.
The camino passes through the old quarter before arriving at another bridge, on the opposite end of which is the municipal albergue and the way out of town.
On the way out of town, it is once more along the N550 (which frankly will be the case frequently between here and Santiago). Leave it to your right at the first bend in the road.