This is still a very big change in a young budgie's life, to be taken out of the comfort of the home they have always been in with their parents/siblings and into a completely different home/environment.
Even for tamed and well socialized young budgies, it's best to give them at the very least a couple of days' time to settle in their new home and to get to know their new family, it's important to not overwhelm the little fellow on the first days at home.
During this time, you can cover the cage on 3 sides (leaving the front part uncovered) and have some background music on to help your budgie feel more relaxed.
While your budgie is in the process of settling in, you can sit close to the cage and talk to your budgie in a calm, positive, encouraging and reassuring way.
If your budgie shows signs of being receptive and curious towards you then you can open the cage's door and slowly place your hand inside the cage and offer your finger for him to step onto it.
Since he is tame, most likely he will automatically step up.
It would be a good idea to bird proof the room before allowing your budgie out in order to minimize the chances of a crash landing/accident.
You don't need to truly grab your budgie with your hands on a regular basis and since you aren't used to handling a pet bird, it's best to take it slow and carefully. At this point and when a budgie is tamed, fledged and independent, there really is no need for a person to take a hold of him/her by grabbing with the hands, in some cases this can even result in a setback in trust/taming, when budgies are grabbed against their will.
A simple step up is much more convenient.
Be sure to check the pertinent info on the stickies at this section of Talk Budgies.
Best of luck with your new little friend!