Order matters here, because two items gate almost everything else. The sequence below is the one that fails least often, but exact office names, appointment systems and timings vary by city and by autonomous community — confirm locally rather than assuming.
Days 1–3: land and stabilise. Book accommodation you can extend — a month, not a year — because you cannot sensibly sign a long lease before you know the neighbourhood. Travala and Trip.com both cover medium-stay apartments; Welcome Pickups takes the arrival-day taxi argument off the table when you have three bags and no Spanish. Get a local SIM on day one: half the appointment systems send confirmations by SMS, and you will spend the month on hold. Use NordVPN when you are doing banking or tax admin on café and coworking wifi.
Days 2–7: the two things that block everything. You need (a) your foreigner identity number and (b) a registration of address at your local town hall — the padrón. In most places the padrón needs a lease or an owner's letter, and the bank, the health system, the gym and the utility company will each ask for one or both of these before they will do anything for you. That is the real dependency chain: address → padrón → number → bank → everything else. Book the appointments the day you land, not the week you need them; slots in Madrid, Barcelona and Valencia go fast. The exact documents each office demands differ by city and we have not verified them per city — ask your local ayuntamiento and your nearest immigration office directly.
Days 5–15: card appointment, if your route requires one. Residence routes generally involve a biometric appointment and a physical card after arrival. Bring your entry visa, passport, photos and your padrón certificate; bring photocopies of all of them. Assume you will be told something is missing once — that is why you start in week one and not week four.
Days 7–20: bank, flat, utilities. With the number and the padrón you can open a Spanish account. Keep Wise running alongside it for the first year, because your income is arriving in another currency and your Spanish account is for rent, utilities and direct debits. Then flat-hunt properly: viewings, not listings. Expect to be asked for proof of income, a deposit and often a guarantee — have your last three months' statements ready as a PDF. Store your bags with Bounce or LuggageHero on the days you are between places.
Days 20–30: health cover, and settle your admin. If you are on private insurance for the visa, confirm the policy is active and that you have a clinic within walking distance — not just a phone number. If you intend to go public later, read the healthcare section below carefully: the convenio especial is not available in your first month. Register with a coworking space if you are going to use one ($105–$160/mo depending on city); Salamanca at 6/10 on the nomad score is exactly where it matters most for meeting people.
One honest warning. Almost every step above depends on an appointment that you cannot control the timing of. Plan for the month to take six weeks. Do not book a flight home, a wedding or a client onsite into week four of your arrival.