What Laurie said.
But a doble dosage of taking in a big breath: it will all be ok. I have gone out for a Camino 6 times now, and I take out my laptop, open Excel, plot possible etapas with distances, albergues, their contact info and amenities I like such as a drier so I can hope for dry clothese should Iend up walking in the rain for days and days. I pull my hair out. But I love it.
Planning is as much fun for me than walking. In fact, when I walk and my feet hurt, and I keep wondering when I will see the edge of town, I wish I was planning, not walking.
Book or not? I do, because I take small steps and walk from 7 to 3 or 4 pm, which means that many long legged people will have arrived much earlier than me (some people walk in the dark in the am only to arrive at noon at the albergue to sit around if you can beleive that
).
But you may start walking when there are few (relatively) departures and therefor less stress to find bed. I would book your first night so you don't have to find a bed as you step off the train or bus while still jetlagged, and then see. I normally book for the next day after my shower. I can then book where my companions are staying, and/or depending on how I'm feeling.
To book phone is better than email, a local SIM card, or a good international plan from your supplier will do it.