Thread by @bhrenton

How to book a vaccination appointment in New York:

This thread will take you through the process of navigating the NYS/NYC vaccination landscape. Before you begin, have your personal details and insurance info (if applicable) ready.
covid19vaccine.health.ny.gov

First, be kind to others. Please, only book a vaccine appointment if you are currently eligible. Beginning today, New Yorkers with certain conditions are eligible to book appointments. Please check this list and prepare documentation (or self-attestation).
covid19vaccine.health.ny.gov/phased-distrib…

Next, some differences. The New York State website books you at New York state-run sites (some of which are in New York City). NYC's Vaccine Finder is merely an aggregate site — it sends you to other pages (including pharmacies) to book your appointment.
vaccinefinder.nyc.gov/locations

Note that currently, pharmacies in New York City do not accept appointments for those with underlying conditions.

For the purposes of this tutorial, I will go through the process for state-run sites.

The link the vaccine page sends you is incredibly easy to remember: …eligible.covid19vaccine.health.ny.gov. This short form to complete is merely for you to verify your eligibility — it does not appear to save your information.
Once you complete this form you will get to …eligible.covid19vaccine.health.ny.gov/Public/provide…

You can then see a list of vaccine sites near you and click to schedule an appointment at that site. Currently only the Javits Center seems to be accepting appointments, no matter what site you click. Scroll down to your desired date — scroll later as less slots are booked.

You can only book one person at a time. This is the golden goose of webpages — you should get to a slot for that day and select your time (currently as of this writing the website currently shows no appointments available, but that could change in minutes).

You'll then be prompted to answer your personal information and insurance information. There will also be a set of pre-screening questions (there are many screens and this process is slightly different for everyone, and unfortunately it is currently not available to show you).

You'll finally be shown a confirmation screen with all the details you entered. Once you confirm your appointment, You should bring your confirmation ticket (electronic or paper, emailed), proof of eligibility, and insurance info. You must complete the NYS Vaccine Form (emailed).

The system times out after 15 minutes of inactivity. It does not have the ability to change an appointment it seems — you must cancel and book a new one.

Yes, this system has flaws. This was just a simulated booking process I did online this morning. It may be different for you.

If the system appears to show that all appointments are booked, try again in a little bit. New vaccine appointments are added regularly.

Finally, thank you to those including @MarkLevineNYC and @darakass who are working hard to demystify and make the process equitable.

Questions/feedback welcome. It's up to all of us to be kind and help each other. Please, only book an appointment when you are eligible. I, like most Americans, am currently not eligible. This is just a simulated experience to show you the process.