We highly recommend starting with a furnished apartment the first 2-4 months after your arrival. As you are relocating with your family, that might also be a good option to search for an apartment for a longer period of time. That way you can deal with the required paperwork of the last steps of your process, settle down, and find out in which area of the city you would like to live.
Our best recommendation for you in Spain is:
Homelike ⭐️ ⭐️ ⭐️
Homelike is the leading platform for long-stay furnished apartments (>1 month) with transparent pricing - no surprises!
Other Providers ⭐️ ⭐️
For more info, also on unfurnished, longer-term housing, please check our Expat Partner Services page here
Helpful rules of thumb:
Never accept a spoken agreement and demand a written contract.
Never pay money upfront before seeing a place in person.
It is not uncommon for landlords to ask you to provide proof of sufficient financial means or for a guarantor to sign the contract with you (make sure you have created an agreement where you are protected)