What is Cryptocurrency (Bitcoin, XRP)?

There are many videos on YouTube, I suggest you watch this one which explains entire protocol

https://www.youtube.com/watch?v=bBC-nXj3Ng4

Is XRP Decentralized?

you can watch David Schwartz, Chief Cryptographer at Ripple who provides the facts and how XRP Ledger is decentralized.

https://www.youtube.com/watch?v=Y7fDEO15MGI

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:

https://www.youtube.com/watch?v=8pJbvhuPrRQ