I always use Google maps satellite view to identify likely camping spots and hour or two before I expect to arrive there.
Near a village, with wild land, not farmed, close to the road but far enough in to be screened. I get there about an hour before sunset and check out a few places leaving my pack by the road. I look for a flat place, screened of possible by bushes or trees, with a smooth surface. I set up the tent and hide my gear under a bush. In Spain and a Portugal people don't walk around much in the evening, they use cars. I save the location in my phone.
Then I go into the village to get food and have a drink. When it's dark I go back, and it's all set up. I use light carefully and I never light a fire, they quite reasonably hate that.
I eat, pop into bed, watch Netflix on the phone. In the morning I have a coffee, pack up, and clean so thoroughly that CSI could find no trace. There's nothing to fear. In the UK or US there might be but violence or mischievous harassment of strangers in rural Iberia is unknown in my experience, and the police are zero tolerant of such behaviour.
You'll have a great time.