Arias admits Colombia teammate Radamel Falcao convinced him about the move.
He said, "Yes, he told me everything, what the club is like, how it works ... That's what brought me here. And I think it's going to help me grow as a player and as a person.
"The main objective is to go match by match. The team has to go out and demonstrate the good squad there is here.
"I can be a very offensive player, but also defensive. In Holland you attack a lot, that's why you saw it's part of me. But with Colombia, you can see how I defended too."