ETFs to Buy?

Hey, I’m turning 20 this month and I’ve 8k saved up that I’m looking to invest in my tfsa. I’ve done a bit of research and found out about ETFs that pay dividends such as BMo premium fund at 7% or CASH. Which is significantly higher than any savings account from a bank. So I’m planning to split my money between these two, am I doing the right thing? I’ve also come across ETFs that pays over 50% in dividends such as MSTY. But I’m not sure if they’re safe over time. I would really appreciate your guys’ advice.