Q. Where can I find information about building codes, especially New York City Building Codes?

The building codes coordinated by the International Code Council Essentials 
(https://codes.iccsafe.org/codes/resources/essentials) provides the international and state by state building codes. 

The Handbooks provide examples of building codes, analysis, illustrations, and intent of the International Building Codes (IBC):

Building codes illustrated: the basics (ebook) https://nyit.on.worldcat.org/oclc/1346543427

Building codes illustrated: a guide to understanding the 2021(ebook) international building code https://nyit.on.worldcat.org/oclc/1269404982

The NYC Codes - Buildings (www.nyc.gov/site/buildings/codes/nyc-code.page)

Building Codes by Congress.gov Building Codes, Standards, and Regulations: Frequently Asked Questions | Congress.gov | Library of Congress

For more information refer to the Building Codes and Standards Guide.