Hi, PetterJohn and quaker (no name? and how do you know it's a male?). Welcome to the forum!
Now, laddering is a no-no, my dear. It's considered a flooding technique (especially for a baby, like you have) and it hugely backfires so I strongly suggest you stop this immediately. Now, you can't start training sessions until the bird is a juvenile (yours is still a baby) so you will need a little patience on this but that doesn't mean the bird is not learning. They are like children, they don't go to school to learn until they are 6 years old but they learn all kinds of stuff before that and so do baby birds. As you stated, he already steps up when asked (and that's one thing he has already learned), you can also teach him to step down and other things by simple repetition and praise when he does them -like coming to you, for example, which is the precursor to teaching them recall. Aside from this, he will learn to master flight (flight is instinctive but they need practice and exercise to develop landing, turning, stopping on a dime, etc techniques and to strengthen their muscles), the lay of the house, the schedule, the routine, to eat new things, etc. I urge you NOT to rush training. It stresses the bird something terrible and, in truth, it doesn't even benefit you or the bird. Years ago, people were all for teaching little babies from cards and these babies could recognize classical music, authors, famous works of art and their authors, even lots of written words by the time they were two years old and everybody was congratulating themselves on the IQ breakthrough of the century! But, by the time they were older, they did not only 'evened out' with 'normally raised' kids, they were found to be behind on social and analytical skills. There is a season for everything and, for a baby bird, it's the season for loving so love your little bird as much as you can (you need to spend many, many hours with him -baby birds are ALWAYS with their parents and siblings, never alone) and learn yourself about him (body language, right diet, likes and dislikes, etc) and establish a steady, never changing routine (essential for a well-adjusted bird).
Now, as to vocalizations... well, you might have the one and only quaker that is not a screamer but I doubt it
They are loud and they like to vocalize more than other species - it's the way they are and there is no training them differently. Yours is not loud because it's a baby but he will. Now, having said that, this doesn't mean that he will scream all the time. They don't as long as they receive the care they need and that means many hours of freedom from cage, several hours of one-on-one, the right diet and, most importantly, a very strict solar schedule with full exposure to dawn and dusk because they are not tropical birds, they come from temperate climate so they are VERY susceptible to the changes in the daylight hours. I have a turquoise female and she is the apple of my eye (don't tell my other birds!
). I love this bird to pieces and show it! So much so that my husband, who hasn't been jealous of my birds for years now (he used to be), is jealous of her! I've always had a preference for quakers and she happens to be super smart, incredibly affectionate, obedient, a great eater and a better flier and so very easy to take care of because she gets along with everybody and everybirdy. She does get a bit loud in the late afternoon but I was born and raised in a South American country where there are wild quakers galore and, to me, their screams are the sounds of home so they don't bother me at all (not that the other parrots vocalizations bother me either because they don't but my parrots are actually very good when it comes to that - even the cockatoo).
Now, tell us a bit about him (or her?). As it is a baby, are you feeding it soft food served warm and fresh twice a day? Is it clipped or flighted? What do you mean by 'teaching it manners'? What 'manners' would that be, specifically? I ask because people sometimes think that it's OK to toilet train a bird when it's actually harmful to do it or that some behaviors are either 'misbehaving' or 'undesirable' when they are entirely natural to birds...