FAA

The FAA occasionally changes processes/documentation and web site...I'll try to collect and post relevant info here:

This page has a link (lower on the page) to reserve/renew N numbers:
https://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_registry/

EAA info on steps to register experimental aircraft:
https://www.eaa.org/eaa/aircraft-building/building-your-aircraft/while-youre-building/registering-articles/overview-of-how-to-register-and-certify-your-homebuilt

Here's info on obtaining an A&P certification using home builder experience:
https://www.eaa.org/eaa/aircraft-building/intro-to-aircraft-building/frequently-asked-questions/a-and-p-license-and-amateur-built-experience

43.13-1B