Start with high-confidence books for boys books, then narrow by subgenre or adjacent topics.
How to Talk to Girls
Alec Greven
Boys Will Be Human
Justin Baldoni
Football With Dad
Frank Berrios
My Big Boy Potty
Joanna Cole
How to Pee: Potty Training for Boys
Dr. Todd Spector
The Boy's Fitness Guide
Frank C. Hawkins, Gheorghe Muresan
50 Things Every Young Gentleman Should Know Revised and Expanded
John Bridges, Bryan Curtis
On Your Mark, Get Set, Grow!
Lynda Madaras, Paul Gilligan
Guy Talk
Editors of Cider Mill Press
What's Going on Down There?
Karen Gravelle
Puberty Boy
Geoff Price