An excellent getting started guide using the official tools: HERE
We highly recommend this ebook, which is regularly updated by the author.
ESP32.net – unofficial site full of useful documentation, tutorials, forum, etc.
ESP32.com – operated by the manufacturer (Espressif)
This guy managed to build an Amazon Echo / Alexa client with an ESP32 and a stuffed rabbit:
- Hackaday post: http://hackaday.com/2017/08/16/alexa-in-a-bunny-rabbit/
- GitHub: https://github.com/MrBuddyCasino/ESP32_Alexa