I need some advice, I had some crypto a few years ago and then sold it and made some good profits and I am now planning to buy some crypto once again and I admit that I am outdated on the crypto world right now. Can someone give a brief explanation of what DeFi is and what are your top 5 coins/tokens and where do you usually trade it. Thanks! 
this article will help you to understand about defi https://deficapital.com/what-is-defi
ryou can trade defi on decentralized exchange such as uniswap or 1inch exchange and cex such as binance or others mate