Congrats on your new family member! i agree with Sailboat, you should slow-down a bit and allow time for him to settle-in and build a close bond with you before you start any type of "training", as it will be much more successful if you have fully earned his trust and he feels completely comfortable with you and in his new home.
***As far as putting your two birds together, please be extremely careful, and if either one of them are biting/nipping/lunging/hissing or being aggressive in any way towards the other then it's best to just not have them out at the same time...And while I know you hope that they will at the very least learn to "tolerate" each other enough to be able to be out of their cages at the same time in the same room, realize that it's quite possible that this may never happen...It's typically the bird that was there first that has the issue, and since your first bird is a Quaker, who are extremely territorial, sometimes that is always an issue...My Quaker came first before any of my other birds, then my Green Cheek, and the two of them are the only two that bonded to each other (and they still fight occasionally)...My Cockatiel and my Green Cheek will tolerate each other, but my Quaker cannot be out with my Cockatiel or my Senegal at all at any time or there will be blood, and the same goes of my Senegal, he's a complete loner and only wants to be out with me, he will attack any of the other birds if they are in the same room with me while he is...I have gotten him to the point (after over 2 years) where he can be out on his own cage while the other birds are also out in the same room, and he'll typically just stay on top of his own cage and he'll be fine, but if any of the others go anywhere near his cage there will be a fight, so I have to be very, very vigilant and we have a daily schedule/routine for my Senegal to have his one-on-one time with me, while the Quaker and the Green Cheek are out together on the gym...
The important thing is to NEVER try to push them/force them to be out together, and if it doesn't work it just doesn't work. If you try to force it that's when injuries happen, and with an IRN and a Quaker, they can do a lot of damage. But overall just slow-down with the IRN and let him go/adjust at his own pace...And also make sure that you are not taking time away from your Quaker, as she has had you all to herself thus far, and if she feels jealousy or like she's being ignored, that's when behavioral issues usually arise...