Hi there and
to Talk Budgies!
It's great to have you here with us; you couldn't have come to a better place to learn even more about these beautiful birds!
It sounds like your little one is settling in just fine, since he's already chirping, beak grinding, preening, etc. However, he's still not used to you, which is perfectly normal given that he's only been with you a few days. Be sure to spend lots of time in the same room with him, doing a quiet activity like spending time on the computer, reading, or just sitting near him and talking to him. Also, you should leave calming music on in the room when you're not there, as total silence means danger to budgies.
Be sure not to try and touch him or put your hand in the cage for at least two weeks while he settles in. After he is more comfortable with you and his surroundings, (after the two weeks), you can slowly begin introducing him to your hand, by placing it in the cage as far away from him as possible, slowly moving it closer over the course of several weeks.
Additionally, be sure to look through the forum's many Budgie Articles and "stickies" (threads "stuck" to the top of each subform for easy reference) to stay up to date on all the best practices for caring for budgies. If you have any questions after reading through anything, be sure to ask as we'd love to help!
We look forward to seeing you and your adorable budgie around the forums!