What lights do I need?

Sorry if this is the wrong place or if it's been asked, I'm very new to marine tanks. I'm looking to set up my first tank in the next little while though. I've got pretty much everything figured out, but the most confusing thing is the lights. I'd be running a 20 gallon tank with a few beginner fish like clowns and live rock for the first while, but I eventually would love to house soft corals eventually. Everywhere I look and search gives me different amounts of light and types and it's so confusing.



Basically, can someone break down in the simplest way, what light(s) are necessary for housing soft corals in a 20 gallon tank? I don't want to go too overboard cost wise, but I want to get what they need.



Also if it's possible, what do I need for lights with only live rock and fish? Just for comparison's sake.



Thanks in advance to everyone!