Best way to get from Barcelona airport to Barcelona Sants train station
I'm travelling to Spain in 51 days! I am using a rail pass to do some travelling within Spain over 10 days (Barcelona --> Valencia --> Madrid --> Barcelona) However, when I come into the Barcelona airport, I am going straight to the Barcelona Sants train station. I was just wondering your opinions on the best way to do this. (In terms of most reliable, most economical, fastest, etc.) What do you think?
Also, because I will have a rail pass for the train rides I previously mentioned, am I allowed to use this pass to take the train from the airport to the train station??
Thankyou so much for your help!!