I'm not a super expert, but I can try to offer some advice on taming.
First things first: Let them set the pace.
when I say this, I mean, don't rush the birds. Let them make the first moves, and don't try to break their comfort zones. If you want them to trust you, they need to feel like they have some control.
In my experience with my own birds and the birds at the store I work at, the best way to start is to move slow around them, talk softly and with genuine care, and give them time to adjust to the sight of you. Sit by them, with your hands folded behind your back, and some distance between you. Just talk to them, or read a book and read aloud so they can get used to your voice. I found that singing works well, too. Over time, you can move your chair a little closer to their cages, to the point where you're next to them. But if they panic when you move closer, take a step back and wait a while before trying again. A little nervous behavior is alright, but panic is not. Once they're getting used to you as a presence and caretaker, you can start working on hand taming. Even if they're not hands-on personalities, it's good to show them that your hands are safe.
I've found a good way to do this is to start with something as simple as leaving your hand on your lap instead of behind your back for a while, then on an armrest, then on a table beside their cage. Same type of thing as when you're getting them used to your presence - birds often see your hand and the rest of you as totally different subjects.
Once they're used to seeing your hands, maybe leave your hand leaned against the bars on the end of a perch - one they have the option to escape from, and the option to voluntarily come investigate.
Another step is to offer them a treat they like from your fingertips - I use things that have length so they don't have to get /too/ close. Gradually reduce this distance until they're comfortably coming over and taking food from your hand.
And keep in mind, this is a process that takes time. Not a day, or a week, but it can take months. If you want them to be truly comfortable with you and feel safe, it's best to let them take the time they need.