Very easily;

- You can vote for it - clicking the 'voting' Star 🌟 under a Given chapter

*then The Star changes color as if you 'made it shine' & it says that 'You voted' - & the author of the book gets a Notification that 'You Voted for Their Book Chapter' 

🔷 You can also Post a Nice Comment 

- under the Chapter of Any Book You Read - telling the Author that 'You like it' :)