After finding and renting a place the next step would be changing the contracts for all the connected utilities. Let’s just hope that everything is connected since it’s much easier and quicker to get everything working.
For us it was changing the contract for water, electricity and broadband into our name.
Some of them are pretty easy and some will just take a bit longer or more follow ups, but you can get it done with almost no Spanish I would say.
If you are using the service of MovingToBarcelona then she will try and help you change all the contracts, but sometimes the companies just want to deal with you and not third parties.