Training with Mango

[ParrotsForLife]

Just a reminder Mango is a Plum headed parakeet who I have almost 4 months now and so far he learned to step up on my arm and the palm of my hand but is scared of the actual hand.Everyday I talk to him and just change his food and water and let him come out on his own.From me talking to him everyday he even learned to say Pretty bird but I haven't heard him say it since the first time maybe he doesn't talk when people are around.So anyway im wondering how will I know when he is ready to move on to the next step and what is the next step?