1. Register your DBA
You will need to register your business name at your local DMV. All you need is the name of your business and roughly $30.
2. Apply for your EIN
For all the information needed to get your EIN, please go here https://www.irs.gov/businesses/small-businesses-self-employed/employer-id-numbers
From there you can decide if your business needs an EIN or not. Applying for an EIN is free.
3. Apply for your Sales Tax Certificate of Authority
Here is a checklist that will tell you all the types of information you may need to provide. https://www.tax.ny.gov/e-services/elcoa/default.htm
Once you have all your needed information ready you can start your application here. https://www.tax.ny.gov/bus/st/register.htm
It will take 10-20 days to get your Certificate in the mail, so don’t wait until the last minute to sign up.
NYS Department of Taxation and Finance
Sales Tax Registration Unit
W.A. Harriman Campus, Building 8
Albany, NY 12227-0155
Phone: (518) 485-2889