Well, the first thing one usually does is to clean up all of the evidence of oil that currently exists. Then run the bike and look for the source. The source will be above where you find the oil drips. If you ride the bike, the oil will blow around and make it difficult to find the source.
Some folks use foot powder or talcum to find leaks, others use dye penetrant developer powder.
Observation skills are key.
All that being said, it does look like, in your case, the oil pan gasket is leaking. You have to be careful with those bolts that attach the oil pan. You can easily strip the threads out of the aluminum engine block.
Use care, clean everything up, apply a new gasket and carefully torque the bolts to spec...it is a very light spec.
For the oil filter, follow the same process of clean up and attachment, spinning the filter to just hand snug and then a half turn or so to tighten.