Loved this idea, I also want to do the same for my daughter but in programming, I was originally looking at using JavaScript but I'm now looking at Python because its much easier and flexible to learn. I know enough to get round java-script but no where to a professional in it.
I would say, the most easiest way would be to do what you're looking at with HTML and CSS, but if you're looking at buttons and the functionality of them you'll need to add in the JavaScript. if you don't want to use the buttons (with JavaScript) I would recommend just doing a simple link:
Code
<a href="#">Click to next page</a> <!-- HTML simple link -->
<br> <!-- HTML button with JavaScript (BELOW) -->
<button onclick="myFunction()" id="myBtn">Read more</button>
This would need to be tied to a JavaScript file. e.g script.js in the same directory, and I would presume the link within the java-script would be your 'myFunction' tied to 'page2', or 'page3'. That's how we do it in python, and the patterns are very similar to JavaScript but I could be wrong so apologises if i should be!
The only thing I would also advise is by checking out W3C Schools, they're got aload of material on learning HTML, CSS, JavaScript. The section I use is 'How to' and its more for advanced for a refresher but you can just grab the code to your liking what ever feature you're developing, and also learn new things.
https://www.w3schools.com/howto/default.asp
Hope this might help or at least point you in the right direction :) Keep up the fab work!