New in crypto, should I go BTC only?

I'm pretty new to Crypto and honestly I always get lost in the sauce when it comes to the Crypto market because of the thousands of coins, projects, and so on.

Not looking for financial advice of course but just trying to understand whats the criteria you guys takes when you want to 'invest' in some crypto/project.

Or should I go straight into BTC. Buy and forget. And become a holder?