You can go to Calella in different ways.
By plane you can fly to Barcelona or Girona. The low cost airlines fly to these 2 destinations. From these airports you can travel to Calella by bus (Sagalis), taxi and in Barcelona by train.
Look for transfers for both airports to Calella here: https://www.suntransfers.com/
From Barcelona you can go by train, take a ticket to Maçanet and change train at Barcelona Sands (same ticket), get of in Calella.
There are also several coach companies that service shuttle service to Spain / Calella. You will then be brought from your departure point to your hotel by bus.
The high-speed train is a possibility. This goes to Barcelona. From here you have bus, taxi or train connection to Calella.
Of course you can also go to Calella by car. The connections via the toll roads are very good.
See You in Calella. We wish everyone a good and safe journey.