Somehow my engine cap got removed and my car isn’t turning on. Am I screwed?

I don’t know how, but, my car didn’t start this morning. So I checked the engine, and the cap for the oil is off. Which is odd, because I’m pretty sure that I screwed it on properly. Putting that aside, I grabbed an old engine cap and replaced the oil that had fallen out and I have my car connected to jumper cables. I’m making some headway here. Does anybody know what properly happened? Am I going to have to get repairs?

EDIT: so sorry I’m panicking a little and forgot to mention. This is a 2015 Kia Soul. The jumper cables worked and my car’s running. Still would like to hear insight