If you want to know how to keep Bitcoin secure, and pretty much everything about Bitcoin, get this book: Mastering Bitcoin: Unlocking Digital Cryptocurrencies by andreas antonopoulos.
First bunch of chapters are a great intro even if you know nothing. Quickly gets into easy but solid protection of Bitcoin assets, then later part of the book is pretty deep, it’s for programmers. But if you haven’t read this book, no matter how little or how much you know about Bitcoin, this book will teach you something useful. Get it!
This book is on O’Reilly media. You know, the computer book company that always has some kind of drawing of an animal on their book covers. I’ve done some writing and editing work for O’Reilly, and here’s a little known fact: their checks have lemurs on them. lol. This little fellow: