Crypto isn't an easy 'get rich, fast' investment. You can make nice profits but you need to take your time to read and learn about crypto. Nobody can tell you what coins you need to buy since everyone has a different investment plan.
Read a lot on this forum, especially the beginners forums.
When looking for coins to invest in look at their marketcap, at their website and read their whitepaper. Understand what the coin is used for and what it's purpose is. Don't go investing in coins because someone tells you to.
It's also a good thing to read up on understanding the charts to look for good times to buy and sell coins.