Start with just giving him treats through the bars until he is comfortable with that. Then giving treats inside or outside of his cage until he is comfortable with it. Then slowly start introducing your finger to step up, he doesn't have to step up right away to get the treat, just come close. Then just work your way from him coming close to get the treat, to reaching over, to eventually stepping up.
This process works best if he is hungry though, so for each session make sure he hasn't eaten for a couple hours by either: letting him eat until his bowl is empty and then waiting a couple hours. or : just take the food bowl away a couple hours before.
This is how I hand tamed my Shyra parent raised baby (flighted too) and I was amazed at how fast she learned.
If you are a visual learner, like I am, I recorded my hand taming process with Shyra here
https://www.youtube.com/playlist?list=PLu2CPZFhJeWo96RAtcIMz8sLhzbDg4EQF