How to find companies to invest in?

Please excuse the potentially ignorant question however I can't seem to uncover any clear answers online about this. I just opened a fake money account on MarketWatch and am about to start trading. Besides your blue chip names and major ETFs, there aren't many companies I have heard of. I am curious about how a beginner should expand their knowledge base to more companies and learn about the basics of the market(how interest rates effect ___, how certain sectors perform in a downturn vs others, what ratios are most important and which metrics matter most(and least) in certain situations, when earnings reports are released, discerning between compnaies' future plans and expectations vs reality, etc etc). Are there any databases or research tools/platforms you use to discover new or existing companies on which you've never heard about previously? Also, where is a good place to start? I'm in the beginnings of attempting to make the transition from playing fantasy sports(similar skillset) into the financial markets. Thank you for the help.