What is Cryptocurrency (Bitcoin, XRP)?
There are many videos on YouTube, I suggest you watch this one which explains entire protocol
Is XRP Decentralized?
you can watch David Schwartz, Chief Cryptographer at Ripple who provides the facts and how XRP Ledger is decentralized.
How to buy, sell and store Cryptocurrency XRP - Ripple?
for example my video - https://youtu.be/gglDda8cbUs
How to setup Ledger Nano X Wallet?
for example this video: