The 30-year-old joined the Arabian team on a season-long loan from Chinese outfit Shanghai SIPG last week.
The striker was forced to look elsewhere after a move to English Championship side Reading FC fell through over reported fitness concerns.
"I’m ready to go, injuries are part of the game, just as long as they don’t retire you," Gyan told the media at his unveiling on Sunday.
"Right now, I’m alright and ready to play football.
"There were some mistakes that I made when I was in China and I don’t want to repeat those mistakes again.
"When I was in UAE before, I was playing almost every game. I want to listen to the staff and what they are going to say.
"I don’t decide on my own, the staff decide when I play."
Gyan is not new to the UAE, having played for Al Ain between 2012 and 2015.
He won the UAE Pro League Top Scorer Award in 2012, 2013 and 2014, the AFC Champions League Top Scorer as well as the AFC Foreign Player of the Year in 2014.
He added: "I’m very happy to be back home, I’m sure everybody agrees with that.
"Al Ahli were my worst enemy before, but right now I’m part of the family.
"I’m coming to work with a staff who I’ve worked with before, who know me much better.
"I’d like to say sorry to the Al Ain fans. We had a great relationship for four years, but it was rather unfortunate I couldn’t come back to Al Ain as people expected.
"But this is part of life. You don’t know what’s going to happen. Right now, I have a new challenge, I need to focus on my career and do what I do best, which is to score goals.
"I’m not perfect, but I’ll work hard to make sure I do that."
The Accra-born has also previously represented Italian sides Udinese and Modena, French side Rennes, English Premier League outfit Sunderland as well as Liberty Professionals in Ghana.