Generally speaking, when bringing in a new pet bird, it's best to give them time to settle in their new cage/environment for at least a couple of weeks.
During this time, you can cover the cage on 3 sides (leaving the front part uncovered) and having some soothing music on. When changing food/water, in order to minimize stress, it would be best to avoid sudden movements with your hands/arms and act as if you are in slow motion. Same thing goes when cleaning the cage.
Depending on the budgie's personality, some can settle in fairly soon and show signs of being receptive to us sooner as well. The amount of time taken to earn a pet bird's trust and to tame will also depend on the individual bird.
In order to get your budgie more used to you, to make the first connection with Yuuto and establish the foundations of trust, you can sit by the cage and talk to him in a calm, positive, encouraging and reassuring way.
Depending on Yuuto's response, you can then take the next step in training when he shows signs of increased curiosity towards you (if he moves close to you when you interact with him). You can slowly place your hand inside the cage and try to offer him a little tasty treat in order to encourage him to step onto your hand/finger.
While going about this, it's important to pay attention your budgie's body language and to react according to it by respecting the safe boundaries set by your budgie.
The information found at the top of the Taming and Bonding section will surely be very useful during your training journey.
Best of luck!