You’ve been chosen to be a CTO, this usually means that you either did well in the company or were hired because of a good track record. So keep doing this + keep things simple, plan ahead, learn from colleagues, share knowledge. Stay humble, confess mistakes, ask for genuine feedback and advice.

Books and blogs have a limited anecdotal value (sometimes it is high but the effort is also high). I’ve learned more from individual HN comments and actual work experience and mistakes than any book.