Awww...Apple is soo cute! We have a yellow sided as well and love him to bits!
You know...just and fyi...and maybe you already know this, but sometimes they will bite and kind of hard when stepping up on your finger...it's how they "test" to make sure what they are stepping up on is "safe" in their mind...and since you are a new owner, he will probably "test" you each time for a few days or weeks even.
With our bird, when he was new to us, he'd reach out to grab and "test" and if it got too hard, I'd say "OUCH, Beeee Niiiice" Generally he'd just step up after that. Once he got to know us he quit with the "testing."
I could tell the difference in his body language, reaching out to grab and test was way different then, get away and leave me alone.
Get away and leave me alone would be more of an aggressive lash out, beak open, squawk, puffed feathers, defensive stance...if you continue with that...then you are asking to loose a chunk of your skin
Reach out and grab and test bite, is usually more of a cautious, grab, bite...harder and a little harder...feathers down and no squawking and usually while "testing" step closer to your finger then once he's decided it's safe...up he goes
Although, I had a tiel once, who'd make you think he was going to take your entire hand off when asked to step up...he NEVER bit, but he'd squeal, open his beak and...I can't describe it, but he'd almost try to scare you, not pecking, but...umm....just moving his head really really fast and tasting, I guess...he'd do this for like 5 or 10 seconds, then jump right up on your hand as if nothing was wrong. It was almost like he was testing to see where he stood and if you jerked your hand away in fear, he'd attempt to bite, but if you remained calm knowing he's not going to bite and said "oh knock it off and get up here..." He would just quit right now and jump up like...Oh, okay...let's go have fun!" LOLOL He was a goofy thing, but I sure loved him.
Anyway...good luck with Apple, he's beautiful!
Toni