It depends on what you want to achieve. If you believe in Polkadot and want to be part of its community and have a say in its future roadmap, then you’ll want to Stake directly on Polkadot. To do this you can stake directly as a validator. But if that sounds way too complicated—which if you’re a beginner, it is—just nominate another validator that is already set up. The simplest route if you just want to see a decent ROI is to stake on an exchange such as Binance or a lending platform like NEXO. This is the easiest way to go about things.