The 19-year-old arrived on Tyneside after leaving La Liga outfit Levante, where he spent last season, and has linked up with the Magpies' Academy.
Guinea-Bissau frontman Cá has already played in both Spain and Portugal, and is now relishing the "different experience" of trying to make his mark in black and white.
"I know it's going to be a really different experience for me. It's a new chapter in my life and I'm very eager to start it here at Newcastle United," he told newcastleunited.com.
"The main goal is to help the team - if my goals are the main thing that helps the team, that's better for me, but the main goal for me is to help the team in any way I can and make sure the team wins."
Cá was a prolific scorer at youth level during his time Amora, with his 13 goals in 31 outings earning him a senior bow in the Campeonato de Portugal. He joined Levante last summer and netted four times for the Los Azulgranas' under-19 team.
And the towering striker believes his style will prove to be a good fit for English football as he looks to further develop at United following what Academy Director Steve Harper said were "valuable" stints in Portugal and Spain.
"I'm a forward who likes to find space, link play and work hard for the team. Scoring goals is a big part of my game, but my focus is always on contributing to the group, whatever helps the team win," Cá explained.
"Here in England, it's a direct and fast style - maybe in one or two touches, you are already in the opposition box. In Spain, similar to Portugal, it's maybe a more horizontal game. But I like this type of direct play.
"At Newcastle, I know it is a style that fits the way I play - the players are not only scoring but also fighting for the club, and it's a way of playing that is familiar to me and I like."
After putting pen to paper, the teenager revealed that the "project here, the lifestyle, and the club's ambition" convinced him to make the switch to Newcastle United.
And he says he is already settling in nicely to his new surroundings after a welcoming introduction to his new club.
"Aside from being a historic club in the Premier League, in recent years it's a club that has played in the Champions League and won the Carabao Cup," he added.
"I like the fact that everyone has come up to me to introduce themselves and say, 'hi Afner' - they know my name, they know who I am, and everyone has been very friendly."
