Someone wanted to learn this too, so Grasp built them a personal learning path.
You can keep exploring this one or create a path like this one shaped around you.
Recommended resources
Module 1
Astro Fundamentals
Module 3
Dynamic Routing and Layouts
Module 5
Building the Core Website Pages
Module 7
Styling and Professional Design
Module 8
SEO and Web Accessibility
Module 9
Performance and Optimization
Module 10
Advanced Features: Search and Forms
Module 11