The former Gunners star replaced Unai Emery - who was axed after a seven-game winless streak - after Freddie Ljunberg's temporary spell in the hot seat, and he admitted there was a "disconnection in many areas".
He told Ian Wright: "Coming into the club in that moment wasn't easy but you mention a key word which is 'energy' and I felt that the energy around the training ground and the stadium wasn't right for this magnificent club.
"I was here and was lucky to play here so everyone first of all has to feel in that way. There was a lot of disconnection in many areas and I wanted to bring everyone together.
"First of all to make everyone understand how lucky we are to be here and then a very clear direction of where we have to be."
Arteta - who insisted a transformation "is happening" for the London club - also commented on rising star Kieran Tierney, and suggested he could be a major player in the future despite a shaky start.
He added: "I'm really looking forward to working with him and giving him the opportunity to play.
"His attitude, his commitment, his will; it's incredible. I think he's going to bring something special to us.
"It's a shame, but it's part of his development. In your career you go through these moments and I challenged Kieran to say, 'Kieran, how are you going to react to that?
"'You cannot feel sorry for yourself that this happened. Okay, the level of expectation now is a bit higher, you have to deal with it.' "