How do you all study stocks, ETFs, etc. to know if they're good investments?

I'm new to the world of investing and I'm finishing putting together my emergency fund. My next step will be to start investing in stocks, ETFs etc., but I still have trouble analyzing whether an investment is actually good or bad. What metrics, indicators, or criteria do you use to evaluate stocks, ETFs RETs before investing? Is there any material you'd recommend for someone who's just starting out? I really want to learn how to do my own analysis instead of just following "YouTubers'" recommen