There is some leaking underneath the engine. My guess is that it's an engine oil leak. Do you think I'm correct? From your experience, what is a good place to start looking for the leak? Thank you!
Looks like oil - simplest place to start is to get the front jacked up, ideally on axle stands or a ramp to make it as safe as possible.
Get a good maintenance lamp and just start looking for oil - the shine gives it away, even amongst the dirt you get on the underside of the engine.
Check the drain valve for the oil pan/sump, and look for drips down the side of the engine block to check for leaks higher up.