I was able to go through few books about bitcoin, articles and links sent here as guide in the forum. One of the best, I have come across is learnmeabitcoin.com. I don’t know if there is any easier one to learn from and understand than this. After all this, I am still yet to understand the concept of open/closed wallet, software/hardware wallet, online/offline wallet. I keep getting them mixed up whenever I try to have a grasp of them.
You could easily find the definitions of these wallets, but if you are looking for a more easy way to understand them, then I would suggest you search for them and use them, which you could do for free. For example, to understand the concepts of open source and closed source wallets, you must know that open source means that it is open to everyone. It does not mean that everyone could use it; instead, everyone could see the code used to make it. While the opposite is true in close source, no one will suggest you use a close source wallet as it might contain flaws or codes that might be faulty.
Software and hardware Wallets are so easy to understand, which means that just like the simple difference between hardware and software, the same difference goes for wallets. There are many wallets, which are physical devices specially made to store assets. And the best way to store assets is with hardware wallets, which are open source.
Online are the ones that are active all the time on the internet, while offline are the opposite of online. There are more to wallets than you might expect. Which are custodial and non-custodial wallets and hot and cold wallets. So learn about them too. Learning such things will help you understand why people used to say ""Not your key, not your coin.