I was referred to this youtube video, which I find fantastic for beginners (like me).
It was made by the creator of learnmeabitcoin.com (if I'm not mistaken).
In simple terms, it covers very advanced topics like locking and unlocking scripts, validation, types of scripts, the basics of stack operators, etc.
These terms can quickly become very technical if you read about them in a book. Because of that, the lessons covered in the video are even more valuable.
The video is a bit lengthy, but it's worth every second of your time. Hope you'll enjoy it as much as I did.