Póvoa de Santa Iria is a large town that the camino tries unsuccessfully to avoid. There are services here but try to keep to the ones along the camino as the arrows are difficult enough to find without wandering off track.
After passing under the A1 a paved road leads you past a pair of small roundabouts before arriving at a large landscaped roundabout.
Keep to your right and take the second exit, putting you temporarily in the direction of Lisbon.
Less than 200m later, cross the road to your left along the Rua Alfonso de Albuquerque and over the railway.
Turn left again to proceed through 800m of an industrial park, at which point the road will end, and you can pick up a path all the way to Alverca.