A few good resources for this. The different positions of "Technical Lead", "CTO", "Engineering Manager" all vary from company to company so I'm not sure what your new role will entail.

1. https://pragprog.com/book/jsengman/become-an-effective-softw..., which had a good conversation here (https://news.ycombinator.com/item?id=22033129).

2. https://managinghumans.com/ by Michael Lopes

3. https://leadingsnowflakes.com/, which also has a good weekly newsletter - http://softwareleadweekly.com/.

4. https://www.udemy.com/course/practical-leadership/

5. https://tomdemarco.com/Books/deadline.html - quite old now, but it's still hugely insightful.

May I wish you the best of luck. It's an exciting and really difficult challenge, but can be hugely rewarding in the end.