Can you go alone, why am I passing through New York? Where is the ticket bought in advance, online?

Yes you can, email to make a reservation

The food, the music, The employments are easy for a good niche. Reservations are preferred

Yes, of course, you can go alone. You can go to the website and make reservations for some shows. All the shows are good. https://www.birdlandjazz.com/