The show made a fair few changes from the books, mostly for the better. Off the top of my head, Avasarala and Draper are introduced earlier in the show, Drummer got the consolidated stories of several other side characters and Elvi Okoye’s and Ashford’s personalities were significantly changed. IMO, Show Ashford is a much more interesting character than Book Ashford. In addition, the season 6 side plot with the kids is told much later in the books.