Hi there! I understand you're having trouble selecting either the curriculum or the book library on the SplashLearn app on your Mac running OS X 10.15.7. Let's see how we can get you back on track.

First, just to get a clearer picture—are you accessing this through a web browser or the SplashLearn app? Also, are you logged in as a parent, teacher, or student?

Meanwhile, here are some initial steps that usually help with issues like this:

1. Check your internet connection to make sure it's stable.
2. Clear your browser's cache and cookies if you are on a browser. On Safari (the default on Mac), you can do this by:
- Opening Safari, going to Safari > Preferences > Privacy.
- Click on "Manage Website Data," then select "Remove All."
- Restart Safari after this.
3. Try refreshing the page after clearing the cache.
4. Make sure your browser or app is updated to the latest version.
5. If using the app and the issue persists, try quitting and restarting the app.

If you've already tried these steps, please let me know. Also, have you noticed any error messages or is the option simply not responsive when clicked?

Once I have more info, I can guide you with more specific solutions or deeper troubleshooting steps.

In the meantime, here’s a related helpful resource from SplashLearn support on troubleshooting common issues: Troubleshooting common tech challenges (web & app) [1].

Let me know how it goes or if you need me to walk you through any step!